What to watch in Wisconsin’s high-stakes primary

A week after progressives scored a victory in Michigan’s US Senate primary , Democrats face another test, this time in the Upper Midwestern US state of Wisconsin .

Voters in the battleground state head to the polls on Tuesday in a primary that will help shape races for governor and all eight US House of Representatives seats in November, as well as the Wisconsin State Assembly and half of the State Senate.

But the biggest spotlight is on the Democratic contest for governor, which has become another proxy battle between the party’s progressive wing and its more moderate establishment.

The results will not only shape Wisconsin politics, but also could offer clues about where Democratic voters want the party to go ahead of November’s United States midterm elections.

Wisconsin is the next major test after progressive Abdul El-Sayed narrowly defeated establishment-backed US Representative Haley Stevens in Michigan’s Democratic Senate primary on Tuesday, renewing questions about whether Democratic voters are moving further left.

This year’s primaries have repeatedly seen outsider candidates outperform establishment favourites, reflecting frustration among many Democratic voters after the party’s losses in the 2024 presidential election and an internal debate happening over US support for Israel. While progressive candidates have won against establishment ones in heavily Democratic states like New York or Colorado, there have been questions about whether more leftist candidates can succeed in US states, like Michigan or Wisconsin, where both Democratic and Republican candidates can have a similar level of support. US President Donald Trump won both Michigan and Wisconsin in the 2024 US presidential election after former US President Joe Biden won them in 2020.

Wisconsin will be closely watched for whether the trend of progressive wins continues.

Whoever wins will likely face Republican Representative Tom Tiffany, a Trump ally who has already been framing the race as a choice between what he calls a “socialist agenda” and “common sense”.