Julia Letlow beat John Fleming 56.8% to 43.2% in Louisiana's Republican Senate runoff on Saturday 27 June, a 13.6-point margin far wider than late polling had suggested1. The runoff had been set for 27 June after Senator Bill Cassidy finished third in the primary. A mid-June Rigamer survey had shown Letlow's 15-point lead collapse to two points; the result buried that reading. Turnout fell 21% from the May primary, to 316,538 ballots2.
The money ran almost entirely one way. The Accountability Project Inc, a super PAC aligned with Governor Jeff Landry, reported $5.9m in independent expenditures against Fleming; Trump's own Securing American Greatness super PAC added $1m3. Super PACs can spend unlimited sums on a race but are barred from coordinating with the candidate they support. Fleming drew essentially no outside support. Jamie Davis took the Democratic nomination 80-20 and advances to the general election.
Set the result against Texas. There a nine-to-one spending advantage for John Cornyn collapsed because Trump had endorsed Ken Paxton, who won by 28 points. In Louisiana the endorsement and the money pointed the same way, and Fleming lost by more than 13 points. Across the cycle's two Senate primaries a Trump endorsement has predicted the winner better than cash has in either direction.
Two contests make a pattern, not a law, and this one cannot separate the endorsement from the spending. What Louisiana shows cleanly is money amplifying an endorsement it agrees with, rather than substituting for one.
