Short Answer

Both the model and the market overwhelmingly agree that Christian Menefee is most likely to be the TX-18 Democratic nominee, with only minor residual uncertainty.

1. Market Behavior & Drivers

This market has experienced a distinct downward trend, with the probability falling from a starting point of 13.0% to its current price of 6.0%. The contract has traded within a range of 6.0% to 21.0% throughout its history. A notable price movement occurred when the price rose from 13.0% to a temporary peak of 15.0% in late April, before experiencing a sharp decline to the current low of 6.0% by early May. This low point of 6.0% now represents a key support level for the contract, while the high of 21.0% has acted as a ceiling on bullish sentiment.
The negative price action appears to reflect the market's assessment of the runoff election dynamics. The low and declining probability is consistent with the candidate being viewed as the underdog, which aligns with context indicating they received a smaller share of the primary vote (44.2%) compared to their opponent (46.0%). An earlier University of Houston Hobby School survey showing the opponent with a significant lead likely reinforces this sentiment. The sharp drop to 6.0% suggests a significant increase in bearish sentiment, although the provided context does not identify a specific catalyst for this move. With 459 contracts traded in total, the market shows moderate engagement, but the sample data points indicate that trading may be sporadic. This pattern suggests price shifts can occur on relatively thin volume, reflecting a clear directional conviction among active traders.
  • Christian Menefee led the March 3, 2026 primary and pre-runoff polling.
  • Christian Menefee significantly outraised Green, with substantial outside spending.
  • Al Green, the incumbent, leverages familiarity in the newly redrawn district.
  • Lower voter turnout is projected for the May 2026 runoff.
  • The redrawn district contains more voters from Green’s previous area.

Who Wins and Why

Outcome Market Model Why
Christian Menefee 94.3% 95.6% Christian Menefee is widely favored to win the Democratic nomination for TX-18.
Al Green 6.0% 4.4% Al Green appears to face long odds in the TX-18 Democratic primary race.

Current Context

The TX-18 Democratic primary led to a runoff election. The Democratic primary for Texas’ 18th Congressional District (TX-18), held on March 3, 2026, did not result in a candidate securing more than 50% of the vote. Consequently, Christian Menefee, who received 46.0%, and Al Green, who garnered 44.2%, advanced to a runoff election scheduled for May 26, 2026 [1][2][3].
Early indicators suggest Christian Menefee is the frontrunner. A University of Houston Hobby School survey conducted on February 13, 2026, among likely Democratic primary voters, placed Menefee at 52% and Green at 28%, representing a 24-point lead. The report suggested that redistricting and geographical factors heavily influenced this gap [4][5]. Furthermore, predictions from Polymarket's TX-18 Democratic Primary Winner market showed Christian Menefee as the frontrunner with approximately 76% probability, while Al Green was second at roughly 25%, reflecting crowd-sourced probabilities [6].
The Democratic nominee for TX-18 remains undetermined. As of May 8, 2026, the Democratic nominee for Texas’ 18th Congressional District has not been definitively established. This is because the May 26 Democratic runoff election is still pending, and its resolution has not been confirmed in the available sources. The nomination effectively remains contested between Menefee and Green until the runoff result is certified [7][3][8].
Sources (8)
  1. 1Texas House District 18 Primary Election Live Results 2026 - NBC Newsnbcnews.com
  2. 2Texas' 18th Congressional District election, 2026 (March 3 Democratic primary) - Ballotpediaballotpedia.org
  3. 3Texas' 18th Congressional District election, 2026 - Ballotpediaballotpedia.org
  4. 4Hobby School Survey: Menefee Leads Green by 24 Points in 18th Congressional District Primary | University of Houstongrad.polsci.uh.edu
  5. 5Christian Menefee opens wide lead over Al Green in Democratic primary for new TX-18, poll finds – Houston Public Mediahoustonpublicmedia.org
  6. 6TX-18 Democratic Primary Winner Predictions & Odds | Polymarketpolymarket.com
  7. 7Texas' 18th Congressional District - Ballotpediaballotpedia.org
  8. 8Texas 18th Congressional District Primary Election Results 2026 - The New York Timesmobile.nytimes.com

2. Price Chart

Historical Price (Probability)

Outcome probability
Date

3. Market Data

Contract Snapshot

A YES resolution occurs if Christian Menefee wins the Democratic Party nomination for the 2026 Texas 18th congressional district House seat (for the full term beginning in 2027); otherwise, it resolves to NO, as these outcomes are mutually exclusive and verified by the Democratic Party and the State of Texas. The market, which opened on February 1, 2026, will close after the outcome occurs or by March 3, 2027, with payouts projected 30 minutes post-closing. Trading is prohibited for individuals with material non-public information or specific affiliations, including campaign staffers, pollsters, and government employees.

Available Contracts

Market options and current pricing

Outcome bucket Yes (price) No (price) Last trade probability
Christian Menefee $0.94 $0.10 94%
Al Green $0.11 $0.94 6%

Market Discussion

The Democratic primary for Texas's 18th Congressional District in 2026 has advanced to a May 26 runoff election between incumbents Christian Menefee and Al Green [1]. In the March 3 primary, Menefee received 46.0% of the vote, while Green received 44.2% [2][3]. Ahead of the March 3 primary, Polymarket data showed Christian Menefee as the frontrunner at 81%, compared to Al Green at 14% [4].

Sources (4)
  1. 1Texas' 18th Congressional District election, 2026 - Ballotpediaballotpedia.org
  2. 2Texas' 18th Congressional District election, 2026 (March 3 Democratic primary) - Ballotpediaballotpedia.org
  3. 3Texas 18th Congressional District Primary Election Results 2026nytimes.com
  4. 4TX-18 Democratic Primary Winner Predictions & Odds | Polymarketpolymarket.com

4. How do Christian Menefee's and Al Green's campaign strategies differ in appealing to voters in the newly redrawn portions of TX-18 for the May 2026 runoff?

Voter Familiarity in TX-18Newly redrawn TX-18 contains far more voters from Green’s old district than Menefee’s [1][2][3][4]
Green's March Primary PerformanceGreen showed domination in Fort Bend during the March primary [1][2][3][4]
Green's Core MessageCalls for unifying '18th and 9th' voters, arguing the districts 'have come together now as one' [5]
Christian Menefee and Al Green are employing distinct campaign strategies for the May 2026 runoff in the newly redrawn TX-18. Green benefits from a higher familiarity among the new electorate, as the district now incorporates a significantly larger number of voters from Green's former district than from Menefee's [1][2][3][4]. This increased familiarity contributed to Green's strong showing in the March primary, particularly in portions of Fort Bend County outside of Harris County [1][2][3][4]. Conversely, Menefee faces the challenge of engaging and persuading a larger segment of voters who were previously part of Green's established base [1][2][3][4].
Candidates employ distinct messaging focusing on unity or results and voting rights. Green's campaign messaging explicitly advocates for the unification of voters from the "18th and 9th" districts, asserting that these areas "have come together now as one" [5]. He frames his political endeavors as a resistance against racism and alleged election rigging by prominent political figures [6]. In contrast, Menefee's strategy for the runoff positions him as a "fighter who can deliver real results" [7]. His approach includes criticism of gerrymandering, which he views as a diversion, and a strong emphasis on protecting voting rights. Menefee has also indicated a willingness to pursue procedural measures, such as suspending the filibuster, to ensure fair access to the ballot [7][8][9].
Sources (9)
  1. 1Christian Menefee and Al Green headed to runoff for Democratic nomination in newly redrawn TX-18 – Houston Public Mediahoustonpublicmedia.org
  2. 2Al Green, Christian Menefee are headed for Democratic runofftexastribune.org
  3. 3Texas' 18th Congressional District election, 2026 (May 26 Democratic primary runoff) - Ballotpediaballotpedia.org
  4. 4Christian Menefee and Al Green headed to runoff for Democratic nomination in newly redrawn TX-18 – Houston Public Mediahoustonpublicmedia.org
  5. 5Longtime Houston Rep. Al Green switching to 18th Congressional District in run for reelection – Houston Public Mediahoustonpublicmedia.org
  6. 6Call for unity and resilience amid redistricting and racism dominates Rep. Al Green’s legislative breakfast | City Government | theleadernews.comtheleadernews.com
  7. 7Menefee and Green head to May runoff in Texas 18th primarytricountyindependent.com
  8. 8Christian Menefee and Al Green, rivals in TX-18, align on aim of strengthening voting rights – Houston Public Mediahoustonpublicmedia.org
  9. 9Menefee and Green battle for Texas' 18th District seat - DefenderNetwork.comdefendernetwork.com

5. What quantitative evidence from the March 3, 2026 primary and pre-runoff polling supports Christian Menefee's position as the frontrunner against Al Green?

Menefee's lead (February poll)24 points (52% Menefee vs 28% Green) [1][2]
Menefee's primary voteApproximately 46% [3][4][5]
Menefee PredictIt probability62% [6]
Pre-runoff polling data consistently supported Christian Menefee as the frontrunner against Al Green. A University of Houston Hobby School poll, conducted from February 3–8, 2026, showed Menefee with a significant 24-point lead, garnering 52% of the vote compared to Green's 28% among likely Democratic primary voters [1][2].
Primary election results confirmed Menefee's strong performance in the initial round. On March 3, 2026, Menefee secured approximately 46% of the first-round votes, narrowly surpassing Green, who received about 44% [3][4][5]. Since neither candidate reached the 50% threshold, a runoff election was necessitated.
Prediction markets consistently favor Menefee as the likely winner of the runoff. A snapshot taken on April 2, 2026, indicated Menefee's implied probability on PredictIt at 62%, significantly higher than Green's 7% [6]. Similarly, Polymarket data showed Menefee at approximately 77–81%, while Green ranged from about 14–22% [7][8][9].
Sources (9)
  1. 1Hobby School Survey: Menefee Leads Green by 24 Points in 18th Congressional District Primary | University of Houstongrad.polsci.uh.edu
  2. 2Christian Menefee opens wide lead over Al Green in Democratic primary for new TX-18, poll finds – Houston Public Mediahoustonpublicmedia.org
  3. 3Democratic Reps. Al Green and Christian Menefee head to a runoff in Texas primarynbcnews.com
  4. 4Christian Menefee and Al Green headed to runoff for Democratic nomination in newly redrawn TX-18 – Houston Public Mediahoustonpublicmedia.org
  5. 5Menefee and Green head to May runoff in Texas 18th primarytricountyindependent.com
  6. 6Who will win the Democratic nomination in the TX-18 House election?predictit.org
  7. 7TX-18 Democratic Primary Winner Predictions & Odds | Polymarketpolymarket.com
  8. 8TX-18 Democratic Primary Winner Predictions & Odds | Polymarketpolymarket.com
  9. 9Vencedor das Primárias Democráticas do TX-18 Previsões e... | Poli-mercadopolymarket.com

6. Based on historical Texas primary data, how might lower voter turnout in the May 2026 runoff disproportionately affect Christian Menefee versus Al Green?

Avg Democratic Runoff Turnout (of primary)34.9% [1][2]
Median decline in TX congressional runoffs since 199449% [3]
Christian Menefee Primary Vote46.0% [4][5]
Lower voter turnout is projected for the May 2026 runoff. Historically, Democratic runoffs in Texas have seen turnout average 34.9% of primary turnout [1][2]. Despite a recent increase in overall Democratic turnout in the March 2026 Texas primary [6][7][8], runoff participation is anticipated to be significantly lower. Congressional primary runoffs in Texas have experienced a median decline of 49% in turnout since 1994 [3]. This suggests a smaller, more engaged, and potentially more ideologically driven electorate for the May 2026 runoff.
TX-18 demographics and candidate profiles present a complex picture. The TX-18 district, primarily inner-city Houston, is ethnically diverse, with Hispanic populations ranging from 43.4% to 48% and Black populations from 29% to 32.2% [9][10][11]. A historical pattern observed in 2020 showed that runoff turnout among voters of color decreased by an average of 43.5%, while white turnout declined by 38.3% [12]. Christian Menefee, advocating a progressive platform [13][14][15], secured 46.0% of the vote in the March 3, 2026 primary [4][5] and recently won a special election runoff in January 2026 [9][16]. His opponent, Al Green, a long-serving U.S. Representative known for his civil rights advocacy and strong community ties [17][18][19], received 44.2% in the same primary [4][5].
Insufficient data prevents determining disproportionate impact on candidates. The available information does not provide enough detail to conclude how these patterns of lower voter turnout, including potential demographic shifts, would disproportionately affect Christian Menefee versus Al Green.
Sources (19)
  1. 1texastribune.org
  2. 2lwvtexas.org
  3. 3fairvote.org
  4. 4ballotpedia.org
  5. 5ballotpedia.org
  6. 6youtube.com
  7. 7kpbs.org
  8. 8ivn.us
  9. 9wikipedia.orgen.wikipedia.org
  10. 10censusreporter.org
  11. 11datausa.io
  12. 12progov21.org
  13. 13cbsnews.com
  14. 14pbs.org
  15. 15ksat.com
  16. 16wikipedia.orgen.wikipedia.org
  17. 17wikipedia.orgen.wikipedia.org
  18. 18house.govalgreen.house.gov
  19. 19house.govalgreen.house.gov

7. Which key political endorsements between the March primary and May 2026 runoff could significantly impact voter turnout for Menefee or Green?

Primary DateMarch 3, 2026 [1][2]
Runoff DateMay 26, 2026 [1][2]
Polymarket Resolution DateOn or around May 26, 2026 [3]
Al Green and Christian Menefee advanced to a runoff for the Democratic primary. After failing to secure a majority in the March 3, 2026 primary, both incumbents will compete in a runoff election scheduled for May 26, 2026 [1][2]. The Polymarket TX-18 Democratic primary winner market is set to resolve around this runoff date [3].
New political endorsements between the primary and runoff are not detailed. Available research does not explicitly specify any new political endorsements that were announced specifically between the March 3, 2026 primary and the May 26, 2026 runoff for either Menefee or Green.
Both candidates received important endorsements prior to the primary. Before the March 3, 2026 primary, Al Green was endorsed by Harris County Judge Lina Hidalgo, an announcement made on February 3, 2026 [4]. Christian D. Menefee also secured an endorsement from the Alliance for American Leadership, which was detailed in a December 2, 2025 release, and this support is anticipated to continue through the runoff campaign period [5].
Sources (5)
  1. 1Incumbents Al Green (D) and Christian Menefee (D) were the top two finishers in the Democratic primary for Texas' 18th Congressional District - Ballotpedia Newsnews.ballotpedia.org
  2. 2Texas' 18th Congressional District election, 2026 (May 26 Democratic primary runoff) - Ballotpediaballotpedia.org
  3. 3TX-18 Democratic Primary Winner Predictions & Odds | Polymarketpolymarket.com
  4. 4Harris County Judge Lina Hidalgo Endorses Al Green Under New CD-18 Map - Texas Scorecardtexasscorecard.com
  5. 5Alliance for American Leadership Endorses Christian D. Menefee for Texas Congressional District 18 - Alliance For American Leadershipa4al.org

8. How do the campaign fundraising totals and cash-on-hand compare between Christian Menefee and Al Green according to the latest pre-runoff FEC filings?

Christian Menefee Total Raised$3.2 million [1][2][3]
Al Green Total Raised$1.2 million [1][3]
Al Green Cash on Hand$265,000 [1][3]
Christian Menefee significantly outraised Al Green in campaign contributions. Menefee's campaign reported raising approximately $3.2 million and spent around $3 million. His cash on hand totaled approximately $256,000. Additionally, Menefee benefited from substantial outside spending, with $2.05 million reported in support of his candidacy [1][2][3].
Al Green raised less but maintained a slight cash-on-hand lead. In contrast, Al Green's campaign reported raising approximately $1.2 million and spending about $1.1 million. While Menefee's total fundraising was significantly higher, Green held a slight advantage in cash on hand, with approximately $265,000 compared to Menefee's $256,000. No outside spending was reported in support of Al Green's campaign [1][3].
Sources (3)
  1. 1newsfromthestates.com
  2. 2ksat.com
  3. 3texastribune.org

9. What Could Change the Odds

Key Catalysts

The Democratic nominee for TX-18 will be determined by a runoff election scheduled for May 26, 2026 [1][2]. U.S. Reps. Christian Menefee and Al Green advanced to this runoff from the March 3, 2026 Democratic primary, as neither candidate received more than 50% of the vote [1][2]. The outcome of this May 26, 2026 runoff will identify the Democratic candidate for the general election [1][2].
Polymarket’s "TX-18 Democratic Primary Winner" listing indicates Christian Menefee as the frontrunner, with an implied probability around 81% compared to Al Green's approximately 14% [3]. This reflects a broad bullish sentiment among traders for Menefee to win the Democratic nomination [3]. Furthermore, the "TX-18 House Election Winner" listing on Polymarket shows the Democratic Party as the leading outcome at about 93%, versus the Republican Party at about 4%, signaling strong trader expectations for a Democratic victory in the general election [4].

Key Dates & Catalysts

  • Expiration: March 03, 2027
  • Closes: March 03, 2027
Sources (4)
  1. 1Texas' 18th Congressional District election, 2026 (March 3 Democratic primary) - Ballotpediaballotpedia.org
  2. 2Democratic primary results for 18th Congressional Districtspectrumlocalnews.com
  3. 3TX-18 Democratic Primary Winner Predictions & Odds | Polymarketpolymarket.com
  4. 4TX-18 House Election Winner Predictions & Odds 2026 | Polymarketpolymarket.com

11. Historical Resolutions

Historical Resolutions: 2 markets in this series

Outcomes: 0 resolved YES, 2 resolved NO

Recent resolutions:

  • KXTX18D-26-GBRO: NO (Apr 20, 2026)
  • KXTX18D-26-AEDW: NO (Apr 20, 2026)