Millions of dollars in outside spending from groups affiliated with Democratic leadership and a dark money network have flowed into the Democratic Senate primary race in Iowa to support State Rep. Josh Turek over a progressive challenger ahead of the election on Tuesday.

The interlinked entities supporting Turek include a group run by Senate Minority Leader Chuck Schumer, despite assurances he was staying out of the race, and the Bench, part of a new billionaire-backed, corporate-aligned Democratic machine claiming to deliver younger leadership to the Democratic Party.

The groups have kept quiet about their joint involvement in the race, likely because of the political optics — voters have grown weary of outside forces putting their thumb on the scale in Democratic primaries. But recent filings indicate they’ve been quietly backing Turek, who’s considered more moderate than his progressive challenger, State Senator Zach Wahls.