Rep. Albert Wynn (D-Md.) and his top challenger squared off in an occasionally contentious debate Thursday night, the first in their increasingly bitter rematch.

The event, sponsored by the Greater Silver Spring Democratic Club, was the first primary debate that Wynn has attended this cycle and featured all five of the candidates vying for the Democratic nomination in the 4th district. But the back and forth between Wynn and lawyer and community activist Donna Edwards (D) at Montgomery Blair High School was the main event of the night.

Edwards almost won the 2006 primary by painting Wynn as a Republican in Democratic clothing and has continued to attack his record on everything from voting to authorize the war in Iraq to his environmental priorities. Since his primary scare with Edwards in 2006, Wynn has done his best to tout his liberal credentials, but on Thursday Edwards called herself a leader who can “exercise good judgement from the beginning … and won’t wait to be corrected after the fact.”

But when Edwards implied that the Congressman can’t say no to special interest groups that contribute to his campaign, Wynn responded that it is Edwards who has close ties to large corporations. He pointed to the financial investments of the Arca Foundation, a Washington, D.C.-based organization that Edwards heads, though she currently is on leave as she campaigns for Congress.

“I can cite to you times where I went against the interest of my donors. … Arca invested in Verizon, Halliburton and Exxon,” Wynn said. “If you’re an executive director and your company invested in Halliburton and Verizon, you have to stand up to it.”

In recent weeks, Wynn’s campaign has also raised conflict-of-interest charges against Edwards, saying that groups that in the past have received grants from Arca are endorsing Edwards this year.

Edwards has said that Wynn’s continued allegations about her endorsements are merely political tactics meant to demean groups that have not come out in support of his re-election. On Thursday, she said Wynn’s claims about Arca’s investments are disingenuous because in her position at Arca she has no control over the foundation’s investments.

“I’m proud to work for the Arca Foundation as an employee,” Edwards said. “I can’t be held responsible for their investments.”

After the debate, Edwards added, “I have a record of service and performance and I operate at a high level of integrity and accountability and I think the Congressman recognizes that he has some deficiencies there, and so I think he’s trying to look for them in me and they’re just not there.”