Richard M. Burr last week bragged about an embarrassing personal detail most politicians would prefer to keep private: His retirement investments had sputtered — badly.

“Let me share with you, when I left the private sector 22 year ago, my retirement account was … worth a little over $200,000,” said the Republican senator from North Carolina, during a debate near Raleigh. “Today, it’s worth $258,000. Not a track record of investment many people in this country would follow.”

In this election, candidates aren’t only better off boasting about poor personal finances, it might be a requirement for winning re-election. The two-term incumbent was responding to a question about how he had personally profited since arriving in office, a criticism his opponent, Democratic nominee Deborah Ross, has made the centerpiece of her campaign.

The attacks have helped turn a once-sleepy contest into a race even Republicans concede could go the Democrats’ way. Polls show Ross effectively even with the GOP lawmaker.

And it’s not just in North Carolina where the criticism has resonated. Across the 2016 Senate map, a bipartisan collection of Republican and Democratic candidates have struggled — often unexpectedly — in the face of attacks that their long tenures in Washington have done more to help their own bottom line than the finances of their constituents.

In Indiana, Democratic former Sen. Evan Bayh’s lead has shrunk, thanks in part to accusations that he abused taxpayer money while in office and profited from his Senate tenure since leaving public life. In Missouri, GOP strategists fear Republican Sen. Roy Blunt will lose re-election because of criticism that his family members are lobbyists.

Even the Senate race in Wisconsin has tightened, according to polls. There, Republican Sen. Ron Johnson has attacked his Democratic rival, former Sen. Russ Feingold ,as a Washington insider who set up a “slush fund” political action committee after losing his 2010 re-election campaign.

The attacks have special resonance at a time of record-high dissatisfaction with politics and the status quo, a desire for change evident earlier this year when insurgent candidates had surprising success in both parties’ presidential primaries. Even GOP presidential nominee Donald Trump, whose poll numbers have fallen amid a series of controversies, has had success attacking Democratic foe Hillary Clinton as a corrupt political insider.  

In Senate races, they’re proving just as effective.

“The last thing a candidate wants to have hung around his or her neck is the albatross of being a self-dealing political insider,” said one Republican strategist, who requested anonymity to speak candidly. “It’s an attack that transcends party lines and it is the kind of dangerous perception that incumbents need to guard against from the moment they take office.”

The attacks resonate no matter which party they target: Burr and Blunt are Republicans, while Feingold and Bayh are Democrats. Bayh served two terms in the Senate while Burr is currently in his second term and Blunt is in his first. (The Missouri Republican served seven terms in the House before entering the Senate.)

Feingold served three terms in the Senate before losing his re-election race to Johnson in 2010.