Rep. Donna F. Edwards emphasized her history as a progressive activist and as a single mother during Monday’s forum. (Mark Gail/For The Washington Post)

Reps. Donna F. Edwards and Chris Van Hollen engaged in a combative forum in Silver Spring on Monday night, facing off for the last time before voters choose a Democratic Senate nominee in Maryland’s April 26 primary.

Both candidates leaned into their strengths in a race that has been neck and neck for months. Van Hollen portrayed himself as a leader in Congress; Edwards emphasized her history as a progressive activist and as a single mother.

More than half a dozen times, Van Hollen, the top Democrat on the House Budget Committee, said he was the one who was leading a fight or putting forward solutions. Edwards, a lawmaker since 2008, poked holes in his record, saying he had compromised where he should not have.

The two engaged in a particularly testy exchange over campaign finance legislation Van Hollen put forward in 2010 that would have required more disclosure in campaign ads aired by outside interest groups, but exempted the National Rifle Association.

Rep. Chris Van Hollen, the top Democrat on the House Budget Committee, portrayed himself as a leader in Congress. (Mark Gail/For The Washington Post)

Edwards argued more forcefully than she has in the past that Van Hollen was wrong to carve out that exception, which was designed to increase the bill’s chance of passing.

“You met with the NRA lobbyists and then you exempted them from your bill,” she said.

His voice raised, Van Hollen responded angrily that Edwards was misleading voters.

“If you think [the legislation] was helpful for the NRA, ask yourself why only two Republicans voted for it” in the House, he said. “I have led the fight against the NRA.”

Every Democrat in the Senate backed the disclosure bill; it fell one vote short of overcoming a Republican filibuster. Van Hollen connected that failure to Edwards’s opposition, saying, “Unfortunately, because of votes like Congresswoman Edwards on the Senate side, we don’t have disclosure today.”

Edwards pushed back with new intensity against a frequent attack Van Hollen makes on her effectiveness. He cites a study from the Lugar Center that ranked Edwards least likely among lawmakers to reach across the aisle.

She said it was “really beneath” Van Hollen to use the “bogus rating,” which is based only on co-sponsorship of legislation.

The two also clashed on trade, with Edwards citing newly released documents on the wealthy using Panama to hide money from taxes as evidence that Van Hollen should not have supported a trade deal with the country. Van Hollen responded that the deal actually increased transparency. (The agreement did not cover tax issues.)

“I do believe it’s important to read an agreement before you decide if you’re for something or against something,” Van Hollen said.

That provoked a sharp response from Edwards, who said it was “spurious” of her rival to “suggest I haven’t read [these trade agreements] and that’s why I don’t support them.”

Both candidates protested or ignored time limits and questions as their exchanges grew heated. The audience of several hundred people was equally high-tempered, cheering and occasionally booing the candidates when they attacked each other.

But the two Democrats agreed more often than they disagreed, on proposals from raising taxes for hedge fund managers to free community college. Most of their differ­ences were stylistic, with Van Hollen drawing on his policy work and Edwards on her lived experience.

Asked about his ability to represent women, Van Hollen noted that when he was first elected to the Maryland House of Delegates 25 years ago, it was with a slate of candidates who backed abortion rights. On the Budget Committee, he added, he now pushes back on Republican efforts to defund Planned Parenthood.

“These are fights that we’re all in together,” he said.

In response to the same question, Edwards recalled seeing a photocopied paper showing employees’ salaries at an early job and learning that her male co-workers were paid more than she was.

“My boss said, ‘Well, they need a raise because they had families,’ ” she said, to sympathetic groans from the audience. “And I knew that was unfair, but I didn’t know what to do about it. So I know something about equal pay.”

On tax policy, she said that as a former secretary herself, she knew that an assistant might pay a higher tax rate than her boss. She recalled standing on picket lines with workers in North Carolina during a unionization fight and talking to her son about dealing with the police.

Van Hollen rattled off legislation he helped pass, from major Democratic initiatives like the stimulus and health care to smaller-bore bipartisan legislation helping disabled people save money and protecting whistleblowers.

The forum came as both campaigns have gotten more aggressive, releasing the first negative ads of the race. A Washington Post-University of Maryland poll released last week gave Edwards a slim, statistically insignificant edge over Van Hollen.

With registered Democrats outnumbering registered Republicans more than 2 to 1 in Maryland, the winner of the Democratic primary will be well-positioned to succeed Sen. Barbara A. Mikulski (D), who is retiring after 30 years in office.

Correction: An earlier version of this story inaccurately reported that two House Republicans voted against the disclosure bill; they voted for it. The story has been corrected.