US Senate Election Betting: Expect Odds To Shift Towards Democrats
Fourteen months into his second term, the Donald Trump presidency is in crisis.
Amidst an unpopular war with Iran, bitter social division and opposition over ICE immigration agents and detention centres, a government shutdown paralysing services and growing fears of an economic crisis (not to mention other scandals concerning cabinet members), every political dynamic seems to be moving against the governing Republican party.
As we head towards November’s mid-term elections, betting sites already rate the Democrats overwhelming 1/6 favourites to win the House of Representatives, but what of their much tougher target?
Whilst their odds on gaining Senate control have shortened, at 9/10 with BetMGM they remain the slight outsiders. Expect that to change very soon.
Mass Protests And Polls Offer Clear Signals
Up to nine million Americans just participated in the third No Kings Protest rallies across the country.
Granted, whilst that tells an important story about organisation and motivation, most were presumably already Democrat voters.
A better guide to decisive, median sentiment lies in polls. Trump’s approval rating just fell below 40% and, given record strong disapprovals, is now rated the worst in presidential history.
The news is even worse in real elections. Democrats continue to hugely overperform and just pulled off an enormous shock in Trump’s backyard.
Trump's approval rating just fell below 40 percent in our tracking for the first time. And his net approval rating is now -17.4, also a new low and down about 5 points over the past several weeks. pic.twitter.com/RFncMOefXZ
— Nate Silver (@NateSilver538) March 30, 2026
US Senate Election Betting: Motivation And Turnout Are Critical Factors
Meanwhile in primaries, Democrat turnout is surging in stark contrast to Republicans.
Turnout is probably the most significant factor when trying to gain an edge on bookies in elections.
Why? Because motivation is extremely hard to measure via polls, and differential turnout favouring one side frequently blindsides them.
In the last three presidential elections, turnout was probably the decisive factor.
In 2024, Kamala Harris lost less due to defections than the inability to turn out the record 81m voters who elected Joe Biden in 2020.
Likewise in 2016, Trump won by the narrowest of margins due to complacency, apathy or division among core Democratic voting groups.
Trump Toxicity May Hurt Senate Races
These small differences in motivation levels matter even more in midterm elections with lower turnout.
Senate races can defy a national trend because the candidates have local pedigree.
However, if Trump’s unpopularity is the key factor - and nobody has ever dominated the political conversation like Trump - it will be very hard for Republican candidates to distance themselves.
Moreover, sentiment within the party is further than ever from the centre. Take the absolutely critical race for the Senate in Texas.
The Democrats have already selected James Talarico - who ran an impressive campaign, reaching across to win potentially decisive voter groups such as Hispanics.
Incumbent John Cornyn would likely be a tougher opponent than controversial Attorney General Ken Paxton, but pressure from Trump’s ‘MAGA’ base has turned the betting for the Republican run-off towards the latter.
Texas Republican Primary Odds:
Nominee | Odds | Probability |
Ken Paxton | 8/15 | 65% |
John Cornyn | 15/8 | 35% |
Prediction Models Still Favour Republicans
The counter-argument to backing the Democrats regards the prediction models which influence betting markets. They label each race as 'likely', 'lean' or 'solid' to either party or if not, a 'toss-up'.
Tallying the current state of play, Center for Politics has the Republicans ahead by 51-46, with the other three rated a toss-up.
Race to the White House has Democrats ahead by 49-48, with three again unrated.
The latter gives the Republicans a 57% chance compared to 43%. To gain control of the Senate, Democrats need 51.
Democrats Have More Scope To Improve
These ratings are based on polls, meaning there can be a lag effect. Therefore, if the current trend persists and becomes evident in the key states, those forecasts will flip.
There is much greater scope for the Democrat tally to rise than fall. The margins in these key races are very tight, leaving Republican leads vulnerable if Democrats continue to overperform expectations.
Specifically, Democrats are highly likely to hold the 47 they already have, and are clear favourites to gain North Carolina and Maine.
Build your daily yard of horses in our new 'Stables Stars' fantasy game below to be in with a chance of winning £100, £50 or £25.
Play Stable Stars Here
Sherrod Brown - a former Senator in Ohio - is clearly ahead in the polls to regain his seat. If doing so, Democrats need to win one from Texas, Alaska, Iowa or, further down the target list, Florida or Nebraska, to reach the 51 target.
If there is significant differential turnout favouring the Democrats, those tougher targets become much more plausible.
That is precisely what legendary strategist James Carville (a keen bettor) is predicting - that the Democrats will overperform across the board. He scores their under/over Senate seats line at 55.
Carville’s prediction is extreme, for sure. Later this year, we can expect betting apps to offer odds on the exact number of seats for each party and that line will be a big outsider.
The basic logic of his argument about overperformance, however, makes solid sense.
It always pays to get ahead of the trend and bet before the odds move, and that is particularly important when it comes to long-term politics markets.
In recent months on these pages, we’ve identified the surge towards the Greens and Plaid Cymru in the UK. Now, it's time to play the Senate.
* Reminder: These are hypothetical odds provided by industry experts.
Who will take control of the US Senate in November? Let us know your thoughts in the comment box below!
