Yevgeny Vindman, who along with his twin brother helped expose then-President Donald J. Trump’s attempts to strong-arm Ukraine into digging up dirt on Joseph R. Biden Jr., won his Democratic primary on Tuesday, according to The Associated Press. He will run in the fall to represent the Virginia district of Representative Abigail Spanberger, who is retiring.

Mr. Vindman, who goes by Eugene, had no governing experience, a point his Democratic competitors made in the primary for Virginia’s Seventh Congressional District. But his name recognition, along with that of his identical twin, Alexander Vindman, helped him raise over $5 million, more than the rest of the field combined.

And his message that democracy is at stake in 2024 proved more persuasive than the push of Democratic competitors — such as two Prince William County supervisors, Andrea Bailey and Margaret Franklin — for governing experience.

Two other races featuring “Save Democracy” candidates went the opposite way. Harry Dunn, who rose to prominence as a Capitol Police officer who waged pitched battles with Mr. Trump’s supporters during and after the attack on the Capitol on Jan. 6, 2021, lost his Maryland House primary last month to Sarah Elfreth, a state senator who ran on her legislative record.

Mike O’Brien, a former Marine Corps officer and fighter pilot who made the preservation of democracy central to his candidacy, lost a Pennsylvania Democratic primary in April to a newscaster, Janelle Stelson, who used issues like abortion access and the price of gasoline and groceries to win the right to challenge a fierce Trump Republican ally, Representative Scott Perry.

In 2018, the Vindman brothers, both lieutenant colonels in the Army and aides on the White House National Security Council at the time, raised internal alarms about a phone call in which Mr. Trump asked Ukraine’s president, Volodymyr Zelensky, to announce an investigation into the business dealings of Mr. Biden’s son Hunter in his country.

At the time, Mr. Biden was widely expected to be Mr. Trump’s opponent in the 2020 election. The call was central to the first of Mr. Trump’s two impeachments, and it vaulted both Vindmans to prominence in liberal circles, though Alexander Vindman was the only brother who testified as part of the impeachment proceedings. Eugene Vindman, who was dismissed from the White House early in 2020, he says as improper retaliation for his whistle-blowing actions, raised a remarkable sum of money for a first-time candidate.

“I sacrificed my military career to expose Trump’s corruption,” Eugene Vindman said in one of his campaign ads.

His election to the House is not guaranteed. Ms. Spanberger, a Democrat who is retiring to run for governor, won the newly drawn district, which runs from Washington’s far-southern suburbs into the countryside north of Richmond, by 4.6 percentage points in 2022. But Glenn Youngkin, a Republican, won the district the year before by 4.9 points en route to winning the governor’s mansion.