Michigan Governor Gretchen Whitmer has endorsed Representative Haley Stevens in the Democratic primary for the US Senate, giving Stevens a significant boost from one of the state party’s most prominent figures. The endorsement matters because the contest is a closely watched test of the Democratic Party’s moderate establishment against its progressive wing, and Michigan is considered an important battleground in the fight for Senate control.

Whitmer said Stevens would work to deliver results for Michigan residents, and was expected to appear with her at a Detroit campaign event. Stevens is competing against progressive candidate Abdul El-Sayed, who has been backed by Senator Bernie Sanders; the Democratic primary is on 4 August. The eventual nominee will face Republican former representative Mike Rogers in November for the seat being vacated by retiring Democratic Senator Gary Peters.