Cardin, Steele Square Off in Televised Debate

"No, I think it was a wrong-headed vote," Steele responded.

Later, Cardin asked Steele, "How would you have voted in Congress if you'd had the chance?" adding that he believes Steele would have backed the president.

"Do not disrespect me and tell me what I would have done at the time," Steele replied curtly.

At times, Zeese appeared to encourage Steele, telling Cardin, "After your first vote, you've been wrong, wrong, wrong."

DePuyt put Steele on the spot over a recent flap about Michael J. Fox's campaign commercial for Cardin, in which the actor urges voters to back the Democrat because of his support for embryonic stem cell research.

In the ad, Fox showed startling signs of Parkinson's disease, contorting as he spoke. DePuyt asked Steele what he thought of talk show host Rush Limbaugh's suggestion, after seeing the commercial, that Fox was acting and exaggerating his symptoms.

Steele called Limbaugh's remarks "a little bit over the line" but said he really didn't hear the entire context of the comments. DePuyt then played the remarks for viewers.

"More than over the line, yeah," said Steele, who, like President Bush, does not support stem cell research that involves the destruction of an embryo.

Cardin said he and Steele have a "fundamental difference" on the topic, saying: "I stood with the scientists. You stood with President Bush."

Throughout the debate, Cardin tied Steele to the president while highlighting his own legislative experience in a "hostile environment" in Congress. Steele portrayed himself as part of the "next generation" of leaders who would not answer to either political party. "For 20 years, sir, you have sat in a seat and waited for the opportunity to lead," Steele said.

After the debate, Cardin's spokesman Oren Shur dismissed the episode over the Purple Line as a "gotcha" moment and a "trivial question."

But the Purple Line is a key issue in Montgomery County and emblematic of residents' deep concerns about jammed roadways. The proposed line would connect Metro's Bethesda and New Carrollton stations.

"There's obviously some homework that needs to be done," said Webb Smedley, chairman of the Coalition to Build the Inner Purple Line. But Smedley said he has seen no evidence that Steele is any stronger on the issue than Cardin.

The Ehrlich administration is studying options, including light rail and a rapid bus system along that route.

Carol Arscott, who has spent years in GOP politics and serves as a deputy transportation secretary in Maryland, said she was stunned by Cardin's fumble. "I think it tells you that he doesn't think the Washington suburbs matter," she said. "He figures he's the Democrat and he'll get the vote there anyway."

Anita Dunn, a Democratic strategist who is not working for Cardin, disagreed. "He had the major points down: traffic and congestion," said Dunn, who lives in Chevy Chase. If Cardin were running for county executive, "it would be a huge problem. But he's running for U.S. Senate and showed the knowledge of the issues facing the Washington suburbs that we would want a senator to have."

Late in the day, Cardin's campaign circulated a list of the congressman's efforts to provide federal funding for state transportation projects, including the Purple Line.