August 11 Primary Preview: The Runoff Math in South Carolina and the Market Puzzle in Minnesota
SC's 10-person GOP field makes a runoff near-certain Tuesday. In Minnesota, markets and polls split on the DFL frontrunner — Senate control at stake.
Two of the most market-active primaries of the 2026 midterm cycle land on the same Tuesday. In South Carolina, prediction markets are pricing something the polls confirm and the ballot math makes nearly inevitable: a second round of voting. In Minnesota, they're pricing something the polls can't quite agree on — which DFL candidate primary voters actually prefer. Both races have November consequences that reach well beyond their state lines.
South Carolina: Thirty-One Days, Ten Candidates, and the Law of the Majority
When Sen. Lindsey Graham died July 11 — having already won the June 3 Republican primary — South Carolina faced an unusual constitutional clock. Under state law, a special primary had to be scheduled within two weeks of the vacancy being certified, sending election officials scrambling to compress an entire Senate nomination contest into roughly three weeks of active campaigning.
The result: a 10-candidate Republican field, a filing window that ran July 21–28, and an August 11 primary where the only rule that matters is the majority threshold. Any candidate who clears 50 percent of the vote wins the Republican nomination outright and is done by Tuesday night. If no one does — and the polling strongly suggests no one will — the top two finishers advance to an August 25 runoff (SC Votes; FEC election notice, July 13).
The prediction market math tells that story more precisely than any single poll. According to our cross-platform consensus, Darline Graham Nordone — the late senator's sister, appointed by Gov. Henry McMaster to hold the seat until a successor is elected — enters Tuesday as the heavy first-round favorite, priced at 68 percent to lead after the initial count. A first-round outright majority is a separate, harder bar: she would need to clear 50 percent to clinch the nomination without a runoff — and every available data point suggests she won't.
Graham Nordone enters Tuesday as the clear plurality leader on every available data point. President Trump endorsed her shortly after the filing window opened, and she carries the recognition of a name that dominated South Carolina Republican politics for more than two decades. AP correspondent Meg Kinnard reported Saturday that Graham Nordone spent the day working the trail in Florence — the kind of old-fashioned retail politicking that defines a short-cycle special election where paid advertising time is limited (AP, Aug. 8).
The latest available poll, from Quantus Insights (Aug. 5–6, 668 likely voters, ±4.0%), put her at 33 percent — with no other candidate above 20. Former state Reps. Russell Fry and Ralph Norman each drew 20 percent; former Gov. Mark Sanford pulled 17 (Newsweek, Aug. 8). The State's review of all available polling reached the same conclusion: with the field scattered across 10 candidates and no one approaching the majority threshold, an August 25 runoff appears almost certain (The State, Aug. 3).
The Greenville Online reported that 12 candidates ultimately filed for the special primary — enough to mathematically shatter any realistic path to a first-round majority without a dramatic consolidation of support (Greenville Online, July 28).
The first-round market's internal pricing reveals a key detail about how traders see the runoff matchup taking shape. Fry, who polls at 20 percent, is priced at just 9 cents to finish in the top two Tuesday — suggesting the market believes his support is softer or more thinly distributed across the state than the topline number implies. Norman, also at 20 percent in polling, is priced at 23 cents to be the runner-up. That consensus implies the most likely runoff scenario is Graham Nordone vs. Norman: a Trump-backed appointee against a former House Freedom Caucus stalwart with established statewide infrastructure.
Whoever wins the Republican nomination will face Democrat Annie Andrews, a Charleston pediatrician, in the November 3 general election. South Carolina has not elected a Democrat to the U.S. Senate since 1998.
Eligibility note: Voters who participated in June's Democratic primary are not eligible for Tuesday's Republican special primary. Those who voted in the June Republican primary, or who sat out both parties' June contests, are eligible to vote Tuesday and in any runoff (SC Votes, July 30).
Minnesota: "The Many vs. The Money" — And What the Market Sees
Minnesota's Democratic-Farmer-Labor Senate primary has been the defining proxy war of the 2026 Democratic Party's internal reckoning. On one side: Lt. Gov. Peggy Flanagan, a progressive who holds the DFL endorsement, the backing of retiring Sen. Tina Smith, and a grassroots organizing operation built over years of state party infrastructure. On the other: Rep. Angie Craig, a centrist who represents a suburban swing district, has dramatically outpaced Flanagan in fundraising, and carries the implicit backing of much of the national party establishment.
The stakes extend to November and beyond: Smith's Class 2 seat hasn't been contested without an incumbent since 2006. The DFL nominee enters the general election as a significant favorite against Republican Michele Tafoya — but whether it's a progressive or a centrist will shape which voters and which coalitions define Minnesota's Senate delegation for the next six years.
The Money Gap
By any campaign finance measure, Craig has dominated the financial race. Roll Call reported she had raised $12.8 million through July 22 and held $3.6 million cash on hand for the primary's final stretch, compared to $6.5 million raised and $1.1 million on hand for Flanagan (Roll Call, Aug. 7).
The gap widens further when outside spending enters the picture. North Star Dawn, a super PAC backing Craig, had spent more than $11.9 million on television and digital advertising by late July, according to the Minnesota Reformer. Flanagan-aligned outside groups, led by the Democratic Lieutenant Governors Association's super PAC, spent approximately $2.4 million (Minnesota Reformer, July 31). The Star Tribune documented that a significant portion of North Star Dawn's funding flows through entities that do not disclose their donors — a fact Flanagan has returned to repeatedly on the trail, while Craig's campaign has countered that Flanagan's own outside support draws from corporate-linked sources (Star Tribune, July 13).
In total, Flanagan's campaign has estimated more than $20 million in outside spending aimed at defeating her — a sum that would be remarkable in any Senate primary race, and is extraordinary in one compressed into a single August primary.
The Endorsement vs. The Polls
Flanagan won the DFL endorsement by acclamation at the party's May 30 convention, after Craig declined to participate in the endorsement process, telling supporters that the roughly 1,200 delegates involved don't represent the full primary electorate. The endorsement conferred the DFL's statewide organizing infrastructure, labor union support, and the public backing of Smith — who called the endorsement her final act of service to Minnesota's Democratic base.
Craig's camp has a competing theory of the race: that cash, advertising, and a track record of winning a competitive swing district matter more than party convention delegates. Her campaign has pointed repeatedly to electability — and has recently drawn the explicit contrast with Abdul El-Sayed's win in last week's Michigan Senate primary, where a more progressive candidate backed by Sen. Bernie Sanders defeated a better-funded moderate. Craig's argument is that she is the Democrat best positioned to hold the seat in November even if she trails among convention delegates.
The polling picture is where the race becomes genuinely hard to read. The most recent nonpartisan survey — KSTP/SurveyUSA, conducted July 29–August 4 among 513 likely voters with a ±5.3 percent margin of error — showed Craig leading Flanagan 42 to 40, within the margin of error (270toWin, Aug. 6). A Public Policy Polling survey, conducted July 23–24 among 672 likely voters and commissioned by a Flanagan-aligned group, showed Flanagan ahead 46 to 32 (Native News Online, July 30). The two polls reach opposite conclusions about the race's direction.
One additional data point: a Swing Voter Pilot survey conducted August 7–8 found Craig leading 60 to 40 among self-identified undecided DFL voters (Valley News Live, Aug. 8). Flanagan's coalition, in contrast, appears strongest among the most committed progressive primary participants — the voters most likely to have attended the DFL convention.
What the Market Sees
Prediction markets heading into Tuesday carried Flanagan as the DFL primary favorite. That implied edge reflects several factors the raw polls don't fully capture: the DFL endorsement machine's track record in driving turnout among the most reliable primary voters, Flanagan's organizing infrastructure across Senate districts, and the explicit parallel that her backers and the market appear to be pricing in from Michigan — where a similar dynamic of endorsement plus grassroots momentum defeated a well-funded moderate by roughly a percentage point last Tuesday (Twin Cities, Aug. 8).
Flanagan's market-favorite positioning represents the market's best estimate that the DFL primary electorate — organized labor, grassroots activists, voters mobilized through endorsement convention infrastructure — turns out at a higher rate Tuesday than the voters Craig has reached through paid media. The SurveyUSA showing Craig within two points is the strongest evidence for a potential upset; the market is effectively betting the turnout composition favors Flanagan's coalition.
Minnesota is one of roughly a dozen states whose Senate outcome will determine which party controls the chamber. Our cross-platform consensus has Republicans at 55 percent to retain the Senate majority, with the Minnesota result among the variables that could shift that picture by November.
Wisconsin: The Third Primary
Wisconsin Democrats will also head to the polls Tuesday to choose their gubernatorial nominee. State Rep. Francesca Hong has consolidated significant support heading into August 11, clearing the field of major challengers in what was already a smaller primary field. The DFL nominee will face Republican Rep. Tom Tiffany in November in a race that nonpartisan forecasters have rated as competitive — Wisconsin's first open governor's race since 2010, with Gov. Tony Evers not seeking a third term (AP, July 2025).
What to Watch Tuesday Night
In South Carolina: The key number is 50 percent. If Graham Nordone somehow clears it — which polling and math make unlikely in a 10-person field — she's the Republican nominee. If she doesn't, watch who finishes second. The first-round market suggests Norman (23 cents) is more likely than Fry (9 cents) to be the runner-up, implying a Graham-Norman runoff on August 25. A Fry surprise would upend that calculus and produce a different ideological matchup for the two-week runoff sprint.
In Minnesota: Watch early returns from the Twin Cities suburbs, particularly Hennepin and Dakota counties — the territory Craig has carpet-bombed with paid advertising. If she's running at or above her SurveyUSA number (42%) in those areas, an upset is plausible. If Flanagan is outperforming expectations in the suburbs on top of her expected margins in more rural DFL strongholds, the organizing theory wins. Results from Senate districts that showed unusually high convention turnout for Flanagan will be an early tell.
Both primaries ultimately set November's table. South Carolina's Republican nominee enters a general election as a heavy favorite regardless of who it is. Minnesota's DFL nominee enters the fall with the structural advantage — but the primary result will define what kind of campaign follows.
Sources: AP (Aug. 8) https://apnews.com/article/darline-graham-campaign-south-carolina-senate-7faae372fd831368c0f2a1af40e5c703 | Newsweek/Quantus Insights (Aug. 8) https://www.newsweek.com/darline-graham-scores-double-digit-lead-in-race-to-replace-brother-12300171 | The State (Aug. 3) https://www.thestate.com/news/politics-government/article316745383.html | SC Votes https://scvotes.gov/u-s-senate-special-republican-party-filing-primary/ | WYFF4 (Aug. 8) https://www.wyff4.com/article/special-primary-election-in-south-carolina/73376189 | FEC notice https://www.fec.gov/help-candidates-and-committees/dates-and-deadlines/2026-reporting-dates/prior-notices-2026/election-report-notice-south-carolina-rep-senate/ | Greenville Online (July 28) https://www.greenvilleonline.com/story/news/politics/2026/07/28/candidates-special-senate-primary-race-lindsey-graham/91079425007/ | Roll Call (Aug. 7) https://rollcall.com/2026/08/07/what-to-know-about-the-minnesota-senate-election/ | Minnesota Reformer (July 31) https://minnesotareformer.com/2026/07/31/state-of-the-race-for-u-s-senate/ | Star Tribune (July 13) https://www.startribune.com/dark-money-mn-senate-democrat-primary-flanagan-craig-super-pac-ads/601863328 | Twin Cities (Aug. 8) https://www.twincities.com/2026/08/08/angie-craig-peggy-flanagan-dfl-primary/ | Valley News Live (Aug. 8) https://www.valleynewslive.com/2026/08/08/swing-voter-data-craig-tafoya-lead-with-undecided-minnesota-voters-ahead-tuesdays-primary/ | Ballotpedia https://ballotpedia.org/United_States_Senate_election_in_Minnesota,_2026_(August_11_Democratic_primary) | Market data: electionpredictions.us cross-platform consensus as of Saturday, Aug. 8.