Ex-Capitol officer Harry Dunn loses congressional primary in Maryland

The former US Capitol police officer Harry Dunn has lost his congressional primary election in Maryland, after a pro-Israel group spent millions of dollars supporting another Democrat in the crowded race.

Dunn, a first-time candidate who gained national attention after publishing a book about his experiences protecting lawmakers during the January 6 insurrection, lost to the state senator Sarah Elfreth in Maryland’s third congressional district.

When the Associated Press called the race at 10.27pm ET, about two and a half hours after polls closed in Maryland, Elfreth was leading Dunn by 11 points. Their 20 other primary opponents lagged far behind.

Related: Pro-Israel Pac pours millions into surprise candidate in Maryland primary

With the primary over, Elfreth is heavily favored to replace the retiring Democratic congressman John Sarbanes in the House of Representatives. The Cook Political Report rates the district, which covers Annapolis and the suburbs of Washington and Baltimore, as “solid Democrat”.

Dunn’s defeat concluded a contentious election that ultimately cost several million dollars. Dunn proved himself to be an impressive fundraiser, bringing in $4.6m across the election cycle. Small-dollar donors made up most of Dunn’s fundraising base, as the candidate often boasted, and his team told the Guardian that the average campaign contribution was $21.64.

Elfreth raised roughly a third as much money as Dunn, bringing in $1.5m, but her candidacy received substantial outside financial help from the group United Democracy Project (UDP), a Super Pac affiliated with the American Israel Public Affairs Committee (Aipac). UDP spent at least $4.2m supporting Elfreth’s campaign, according to documents filed with the Federal Election Commission.

Elfreth’s victory comes one week after UDP notched a major win in Indiana, with the primary loss of the former Republican congressman John Hostettler. UDP spent $1.6m in its effort to prevent Hostettler, who was criticized for making comments that were deemed antisemitic, from returning to the House. In March, UDP suffered a defeat in California’s 47th congressional district, where the Democrat Dave Min advanced to the general election despite the Super Pac spending $4.6m against him.

UDP’s decision to invest in the Maryland primary came as somewhat of a surprise, given that neither Dunn or Elfreth had been especially outspoken about US-Israel relations or the war in Gaza. However, their fellow candidate and labor lawyer John Morse, who received the endorsement of senator Bernie Sanders, made his support for a ceasefire in Gaza the focal point of his campaign. (When the primary race was called, Morse had captured just 1% of the vote.)

Morse’s candidacy may have motived UDP to get involved in the race. In a statement to HuffPost last month, UDP’s spokesperson acknowledged Dunn’s “support for a strong US-Israel relationship” but suggested concern about other candidates in the primary.

“There are some serious anti-Israel candidates in this race, who are not Harry Dunn, and we need to make sure that they don’t make it to Congress,” a spokesperson, Patrick Dorton said.

Faced with an onslaught of UDP spending in support of his biggest rival, Dunn chose to turn the Super Pac’s involvement in the primary into a campaign issue. In a statement to the Guardian last week, Dunn framed the infusion of Super Pac money into the race as a threat to democracy and an insult to the legacy of Sarbanes, who made campaign finance reform one of his top priorities over his nine terms in Congress.

“These groups, funded by Republican extremists, are coming after our movement to protect American democracy. Congressman John Sarbanes spent his career trying to get dark money out of politics; now those same dark money groups are trying to buy this seat,” Dunn said. “When I get to Congress, I know who I will work for and I will be accountable to – and it won’t be the dark money donors or the special interest groups.”

But that argument was not enough to carry Dunn to victory, and Elfreth now appears poised to win a House seat in November.