Longtime Rep. John Larson (D-CT) is facing a serious challenge to his political survival from former Hartford, Conn., Mayor Luke Bronin, the latest in a wave of challengers to make the argument for generational change in the House of Representatives. Larson, 78, has held his House seat since 1998.

Despite their age gap — Bronin is 47 — the two are generally ideologically aligned and were once allies, though Larson has been trying to outflank Bronin from his left, pointing to support the former Hartford mayor has received from wealthy backers. The race has also split local Democrats: Sen. Chris Murphy (D-CT) is defending and recorded an advertisement for Larson, but Bronin won the Connecticut Democratic Party’s endorsement in a party convention, a major upset.

Bronin has argued that the current political environment requires more active and energetic representation. Larson has emphasized his record and experience in office and has had to campaign more aggressively than in decades, according to local reporters.

Larson was among the House Democrats who voted last month against an amendment to cut off all U.S. aid to Israel, and is endorsed by AIPAC. At the same time, he’s been critical of the human rights situation in Gaza and opposed the Iran war. The district is home to the largest concentration of Jews in the state, largely in the Hartford area.

“Yes, I voted in favor of making sure that Israel, our ally, is going to get the aid from the United States that it needs. But the Palestinians need humanitarian aid, and [President] Donald Trump has got to enforce the law,” Larson said of the amendment vote in a recent debate. He urged the administration to enforce the terms of the ceasefire deal between Israel and Hamas, including to ensure that Israel is providing sufficient humanitarian aid to the Palestinians. 

Bronin criticized Larson for his vote, adding that if elected, he would not support any further offensive aid to Israel, though he said he supports defensive systems that protect civilians such as the Iron Dome.

“Trusting Donald Trump to do the right thing is a mind-blowing example of putting hope over all of the evidence in front of us,” Bronin said during the debate. “We have a president who is empowering an extremist Netanyahu regime that sees war as the answer to everything — most of all Netanyahu’s political interests.”

Bronin led Larson by eight points in a May poll that was  sponsored by a group backing Bronin. The challenger has also received a boost from outside spending. VoteVets has spent $1 million boosting Bronin, with other groups also intervening in support of him, allowing him to dominate the airways, according to the Cook Political Report. Other groups have come in to support Larson, but are spending less on the race.

Bronin also holds an edge in fundraising — atypical for a challenger against a veteran incumbent — bringing in $3 million during the campaign cycle to Larson’s $2.7 million as of late July.

Both Democrats described the war in Iran as illegal and said they opposed it during the debate. 

Bronin also emphasized his work in the Obama administration as assistant secretary of the treasury for terrorist financing and financial crimes. He said he had traveled globally to rally support for Iran sanctions that ultimately yielded the Obama-era Iran nuclear deal “that would have kept us safer if Donald Trump had not ripped it up.”