Sherrill, a graduate of the Naval Academy who spent nearly a decade flying helicopters for the Navy, cited her military service as the main influencer to her decision. It’s a choice that for Sherrill—and other freshman Democrats who, like her, flipped Trump districts in 2018—could cost her re-election.

“My military service taught me to put our country—not politics—first, and my time as a federal prosecutor taught me about the importance of the rule of law and of justice,” Sherrill said in a statement. “In short, the president has violated the very principles upon which our country was founded. He put his own political interests before our country, and has disregarded the rule of law and the powers granted to Congress by our Founding Fathers.”

Sherrill was a key component in helping the House to launch its impeachment inquiry. Along with six other freshmen lawmakers with national security or military service backgrounds, Sherrill was part of an op-ed that made the case for why Trump’s dealings with Ukraine warranted an investigation into whether he should be impeached.

Sherrill joins the likes of at least nine other vulnerable Democrats who within the last day have also announced they’ll vote to impeach Trump. The lawmakers include Kendra Horn of Oklahoma, Anthony Brindisi of New York, Elissa Slotkin of Michigan, Chrissy Houlahan of Pennsylvania, Joe Cunningham of South Carolina, Jason Crow of Colorado, Andy Kim of New Jersey, Abigail Spanberger of Virginia and Ben McAdams of Utah.

While there’s been a steady stream of swing district Democrats who’ve pledged their support for impeachment since the two articles—abuse of power and obstruction of Congress—passed the House Judiciary Committee last week, there is one member who will be leaving the party over his opposition to impeachment: Jeff Van Drew.

The freshman from New Jersey intends to become a Republican after internal polling among his constituents painted a bleak picture for the moderate’s re-election chances. Republicans have touted the defection as evidence Democrats lack the support to justify impeachment.

Still, with just a handful of vulnerable House Democrats remaining mum on how they plan to vote, it appears likely that the final number of Democratic lawmakers who break rank to oppose impeachment will be minimum.