Baumgartner said Cantwell was symbolic of the partisan gridlock in Washington, D.C.
"If she can't work with the tea party, they're not going away, regardless of what you think of them," he said.
On climate change, Baumgartner said "it is clear" that it is happening but it was unclear whether it was caused by mankind. Still, he said steps must be taken to deal with rising carbon emissions.
Cantwell said she worked with Sen. Susan Collins, R-Maine, on climate change legislation. She said rising temperatures could affect energy prices in Washington state.
"I want us to diversify off fossil fuels," she said. "We need a process to protect consumers of the future." She said she's confident a green energy economy can help create jobs.
Cantwell is favored to win re-election, and she has raised far more money than Baumgartner, a fact that the challenger noted during the debate when speaking about campaign finance laws.
"Obviously I'm at a tremendous financial disadvantage in this race," he said.