Trump won McAdams' district by 7 points in 2016, though Republicans typically hold an even bigger advantage on the ballot. McAdams won by roughly 700 votes over former Rep. Mia Love in 2018.

Later on Monday, Cunningham told the Post and Courier that he, too, would support both articles of impeachment.

“I’ve waited and waited and I have not found any evidence they submitted compelling at all,” Cunningham told the South Carolina newspaper. “At the end of day, this is simply about the rule of law, whether we’re a country with laws or not and what type of precedent we want to set for future presidents.

Cunningham and McAdams are among 31 House Democrats whose districts went for Trump in 2016 — a group that has faced immense pressure from GOP groups, including millions of dollars of TV ads, in the run-up to the House’s impeachment vote.

Roughly half of those members have already declared they will support impeachment, including Reps. Elissa Slotkin (D-Mich.), Andy Kim (D-N.J.) and Abigail Spanberger (D-Va.), who made their announcements earlier Monday.

“The President’s actions violate his oath of office, endanger our national security, and betray the public trust," Spanberger said in a statement. "Because of the oath I swore to support and defend the Constitution, I will be voting in favor of both articles of impeachment."

Other Democrats who have yet to say how they’ll vote include Kendra Horn of Oklahoma, Anthony Brindisi of New York and Jared Golden of Maine, whose districts all went for Trump by more than 10 points.

Rep. Collin Peterson of Minnesota and Jeff Van Drew are the only Democrats who voted against launching the impeachment inquiry, and Van Drew is switching to the GOP later this week.

McAdams’ announcement comes just hours after Dan Hemmert, his most serious GOP challenger, abruptly withdrew from the race.

Hemmert, the Utah Senate majority whip, had been the only candidate in the half-dozen person GOP primary field to be named to the NRCC's "Young Guns" program.

“Dan Hemmert was handpicked by Washington Republicans to run in Utah's 4th Congressional District, and his decision to drop out of the race underscores just how difficult Representative Ben McAdams will be to unseat in November,” DCCC spokesperson Brooke Goren wrote in a statement.

Cunningham achieved one of the most shocking upsets of 2018 when he beat Republican Katie Arrington by less than 4,000 votes in a coastal South Carolina district the president carried by 13 points.

He benefited from some unique circumstances that helped him flip a GOP stronghold. Arrington’s support for offshore drilling turned off some reliable Republican voters. She also got into a serious car accident that left her sidelined in the summer before the election.

House Republicans have made Cunningham a top 2020 target and several candidates have lined up to challenge him, including Nancy Mace, a state representative and the first female graduate of The Citadel. She had raised more than $360,000 for her campaign by late September.

Ally Mutnick contributed to this report.