With incumbent Senator Gary Peters (D) set to retire at the end of this term, Michigan can expect a competitive Senate race to fill his seat in November. Leading up to November, the Michigan Senate primary has seen $98.2M in ad spending and reservations, making it the third-most expensive Senate primary on record and the second-most expensive in the 2025-2026 cycle, only behind Texas Senate. Notably, this election has seen the most Democratic spending out of all the Senate primaries this cycle. Over 20 advertisers have spent a combined $80.8M in support of Democratic candidates. Meanwhile, nine advertisers have spent $17.1M supporting sole Republican candidate Mike Rogers.
The $98.2M in total Michigan Senate Primary ad spending has more than tripled the state’s previous record for most expensive non-presidential primary. Notably, the Michigan Governor Primary has also broken this record, drawing $63.7M in ad support during the primary window. As a whole, the $194.3M in Michigan’s 2025-2026 primary ad spending has been the most of any midterm cycle in Michigan history.
Detroit, the market with the eighth-most spending nationwide this cycle, has seen $39.1M in spending targeting the primary. Following Detroit is Grand Rapids-Kalamazoo-Battle Creek ($20.9M), Lansing ($10.8M), and Flint-Saginaw-Bay City ($9.9M).
On the Democratic side, Congresswoman Haley Stevens (MI-11) has seen a majority of ad support targeting the primary, at $63.9M. In total, 78% of all spending targeting the primary went towards supporting Haley Stevens. Her opponent, former public health official Abdul El-Sayed has seen $7.5M in ad support. Prior to dropping out in early July, Michigan State Senator Mallory McMorrow saw $9.0M.
On the Republican side, former Michigan Senate candidate Mike Rogers has seen $17.1M in ad support.
Outside Groups Pour In
Spending by outside groups makes up 88% of all spending targeting the Democratic primary. Stevens saw $60.5M in ad support from outside groups, making up 97% of her total ad support, compared to 28% of El-Sayed's ad support coming from outside groups. In total, Stevens has seen ad spending in support of her from eight different groups, the highest spending groups being United Democracy Project ($31.7M), A Stronger Michigan ($16.1M) and Center for Democratic Priorities ($6.5M). The $31.7M from United Democracy Project represents the group’s largest investment in Congressional races on record, more than doubling what they spent to primary Jamaal Bowman in the New York 16th House primary last cycle.
El-Sayed's campaign has spent $5.2M on ads, $3.0M more than the Stevens campaign spent. He’s seen ad support from Fighting for Michigan PAC ($1.2M), American Priorities ($581K) and Working Families Party ($244K).
In the Republican primary, Mike Rogers’ campaign has spent $1.5M but received $15.6M in PAC ad support, including $9.8M from Americans for Prosperity Action, $4.3M from Great Lakes Conservatives Fund and a combined $1.4M from six other groups. Ads supporting Rogers placed by PACs constitute 91% of his total ad support.
Trump Dominates the Airwaves
Ad messaging in the Democratic primary has remained largely positive, with just 12% of broadcast airings being negative or contrast ads. Despite the low amount of negative and contrast airings, both camps have gone on the attack in their ad messaging. United Democracy Project has targeted El-Sayed over his past criticism of Democrats, while El-Sayed has attacked Stevens on the matter of ICE.
The top messaging themes in the primary are Donald Trump, ICE, healthcare, special interests, and Barack Obama. Nearly 73% of all broadcast airings were about Trump and the candidate's opposition to him.
Trump isn’t the only national party figure to be brought up in broadcast ads targeting the primary. The Stevens campaign and pro-Stevens groups have released numerous spots highlighting Obama’s past support of the Congresswoman and her work in the Obama administration. Meanwhile, the El-Sayed campaign released an ad touting his early support of Kamala Harris’ 2024 presidential campaign.
Looking Ahead
Currently rated a “toss up” by Cook Political Report, the Michigan Senate General Election will unquestionably be a critical battleground for both parties vying for control of the Senate in November. Both parties have already drawn lines in the sand for November. Democratic group WinSenate has booked $17.4M to support the winner of the Democratic Primary, while the Republican Senate Leadership Fund super PAC has booked $27.8M.