Allegations of domestic abuse against Rep. Keith Ellison, the deputy chairman of the Democratic National Committee and the first Muslim elected to Congress, continued to rock the race for attorney general in Minnesota as voters headed to the polls on Tuesday.

Key primary races were also underway in Connecticut, where Republicans hope to snatch yet another governorship in deep-blue New England, as well as Vermont and Wisconsin. The contests, which include House, Senate, and gubernatorial primaries, are a major test of President Trump's influence in the Midwest ahead of the November midterm elections, as several candidates fight to present themselves as the most pro-Trump choices.

But the abuse allegation against Ellison, who has vowed to fight President Trump's agenda by seeking to restore ObamaCare and net neutrality regulations, loomed especially large nationally. Critics accused party leaders of staying mum on the situation for political reasons.

State attorney general positions like the one Ellison is seeking are increasingly influential nationwide, as state governments escalate their legal assaults on the Trump administration over a variety of policy matters.

Ellison has long been a leader in the Democratic Party. The divorced 54-year-old is a six-term congressman who became deputy chairman of the DNC last year after falling just short of the top job. He was among candidates rushing to file for Minnesota's attorney general office after incumbent Lori Swanson made a late decision to run for governor.

But his efforts to secure the Democratic nomination for Minnesota attorney general were upended this weekend, when the son of Ellison's former girlfriend, Karen Monahan, posted on Facebook that he had seen angry text messages from Ellison to his mother and a video that showed him dragging Monahan off a bed.

Ellison denied any abuse or threatening messages and said the supposed video "does not exist because I have never behaved in this way."

Late Tuesday, just hours before polls closed in Minnesota, the DNC issued its first reaction to the allegations.

"These allegations recently came to light and we are reviewing them," the DNC told NPR. "All allegations of domestic abuse are disturbing and should be taken seriously."

Meanwhile, former DNC communications director Luis Miranda told NPR: "The party has no choice but to suspend him at a minimum until they figure out what's going on. Frankly, it would be malpractice not to. We've made it clear we're going to take these accusations seriously."

The DNC's delayed response to the episode had prompted backlash from top conservatives over the weekend.

"It’s great to be the DNC," wrote former George W. Bush press secretary Ari Fleischer on Twitter Monday. "If Ellison were a Republican, the press would have knocked over the doors of the RNC demanding a statement. But the DNC’s co-chairman? No comment from the DNC. No feeding frenzy from the press."

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Former Trump press sectretary Sean Spicer agreed, saying: "Not only is the DNC silent, the media has failed to cover it: DNC Silent As Deputy Chair Ellison Battles Domestic Abuse Allegations."

On Tuesday, Spicer added, "So the Sierra Club has issued a statement about the allegations against the Deputy DNC chairman......but the DNC still has not ....and most major 'news' outlets don’t seem to have an issue with that."

With a huge fundraising advantage and star power over his opponents — including a visit from 2016 presidential candidate Sen. Bernie Sanders — Ellison was considered the heavy favorite before the Monahan allegation surfaced.

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Monahan, a Minneapolis political organizer, said via Twitter that her son's posting was "true." But she later told Minnesota Public Radio News that she would not release the video because it is "humiliating."

Also running in the Democratic primary were state Rep. Debra Hilstrom, former Department of Commerce Commissioner Mike Rothman, former Ramsey County Attorney Tom Foley and attorney Matt Pelikan.

Governor's races in Connecticut, Vermont, Minnesota, and Wisconsin

Connecticut is ground-zero for Republican efforts Tuesday to continue their gains in deeply progressive New England. Republicans hold the governorships of four out of six states in the region, including Vermont, Maine, Massachusetts, and New Hampshire -- which the GOP attributes to its candidates' fiscal conservatism, moderate social policies, and Democrats' financial mismanagement.

Even though Connecticut voted for Hillary Clinton by double-digits in 2016, the state's governor, Dan Malloy, is deeply unpopular, oweing to high taxes and an ongoing budget crisis. Malloy declined to seek a third term.

Danbury Mayor Mark Boughton, former First Selectman Tim Herbst, businessman Steve Obsitnik, former investment banker Bob Stefanowski and former hedge fund manager David Stemerman are the Republicans looking to succeed him. They have disagreed on key issues, such as whether to eliminate the state's income tax.

In Vermont, Republican Gov. Phil Scott is favored to win re-election, despite drawing the ire of conservative critics by signing the state's first major gun control law earlier this year. No sitting governor has been defeated in Vermont since 1962.

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Two Democrats are vying to make history in the state on Tuesday, despite long odds. Christine Hallquist is vying to be the first openly transgender woman to serve as a U.S. governor. A former CEO of the Vermont Electric Cooperative, Hallquist is focused on tackling climate change and implementing universal health care in the Green Mountain State.

And a 14-year old boy, Ethan Sonneborn, has also thrown his hat into the ring, taking advantage of the state constitution's lack of an age requirement to seek the governorship.

Meanwhile, in Minnesota, Tim Pawlenty -- who briefly ran for president in 2012 -- is hoping to stage a political comeback and become Minnesota’s governor again, in a race to replace outgoing Democratic Gov. Mark Dayton that Fox News considers a tossup.

Pawlenty has said he voted for Trump, but later called the president "unhinged and unfit" -- which may alienate conservatives in the state.

During the campaign, Pawlenty and Hennepin County Commissioner Jeff Johnson have spent much of their time in the campaign fighting over who previously insulted the president the least. Both men criticized Trump during the 2016 campaign, with Johnson calling the president a "jackass" and Pawlenty pulling his support after the "Access Hollywood tape" of Trump bragging he could grope women because he was famous.

Now, they both say they voted for Trump in the end and would welcome the president's support. Trump has not endorsed either candidate.

Pawlenty is seeking the nomination against several other Republicans, including Jeff Johnson, who was the party’s 2014 gubernatorial nominee. On the Democrats’ side are: state Rep. Erin Murphy, Minnesota Attorney Gen. Lori Swanson and U.S. Rep. Tim Walz.

Finally, in Wisconsin, Democrats are making yet another effort to unseat Republican Scott Walker, a well-known union buster who is seeking a third term. A bevy of Democrats with some high-profile endorsements are competing for the right to take him on in November.

House and Senate races

A series of House and Senate races are also underway Tuesday. Broadly, Republicans are looking to make gains by winning some House seats in Minnesota, while Democrats are targeting House races in Wisconsin and Minnesota.

Perhaps the most notable races are in Wisconsin, where Democrats are fiercely competing for the nomination to succeed outgoing Republican House Speaker Paul Ryan, who announced his resignation earlier this year. Teacher Cathy Myers and union leader Randy Bryce are locked in a battle for the Democratic nomination; Ryan-backed businessman Bryan Steil is leading the GOP pack.

Also in Wisconsin, Republicans Kevin Nicholson and state Sen. Leah Vukmir are seeking to oust Sen. Tammy Baldwin in November. The seat is considered essential for Democrats if they want to hold the Senate, and in a sign of the race's importance, more than $35M has been spent in the race.

The state party is backing Vukmir, an ally of Gov. Scott Walker. But her critique of Trump as "offensive to everyone" during the 2016 primaries has provided an opening for Nicholson, a Marine veteran and former Democrat who spoke on behalf of Vice President Al Gore at the 2000 Democratic National Convention.

Fox News' Kaitlyn Schallhorn and Associated Press contributed to this report.