Despite a multimillion-dollar advertising blitz from one challenger and an aggressive grassroots campaign from another, U.S. Sen. Ben Cardin of Maryland remains among the safest incumbents in the nation as he runs for a second term, according to a new poll.

Potomac businessman Rob Sobhani, running as an independent, has not cut significantly into Cardin's lead though he has pumped millions of dollars of his own money into the race. He may be helping the Democratic incumbent by siphoning some voters away from Republican challenger Daniel Bongino.

Half of likely voters who responded to the poll said they will back Cardin, compared with 24 percent for Bongino and 14 percent for Sobhani. One in ten voters said they were undecided.

With a week to go before the Nov. 6 election, Cardin is outperforming his competitors in virtually every demographic group, including among whites and blacks, men and women, young voters as well as seniors. And while Bongino and Sobhani have branded themselves political mavericks, it is Cardin who is winning the highest percentage of independent voters.

"I don't think either one of these candidates, based on looking at this polling data, are demonstrating any particular pockets of strength," said Steve Raabe, president of OpinionWorks, which conducted the statewide telephone survey of 801 likely voters from Oct. 20 to Oct. 23.

Cardin, a former state lawmaker, has called for spending cuts and taxes to address the nation's fiscal problems as well as more federal investment in education, research and infrastructure. Bongino has promised to oppose new taxes and reduce government spending while Sobhani believes private sector investments can help curb stubbornly high unemployment.

Cardin's margin is in contrast with other Senate races across the country. Down-to-the-wire uncertainty in states like Virginia and Nevada has put control of the chamber up for grabs, even as Democrats make progress toward Republican-held seats in Massachusetts and, more recently, Indiana.

"The last two credible polls have provided conclusive evidence that despite Mr. Sobhani's multi-million dollar effort, the momentum is clearly with our grassroots campaign," Bongino said in a statement, referring to polls by The Sun and The Washington Post that had similar results. "With Senator Cardin barely reaching the fifty percent mark, it is clear Mr. Sobhani is now acting as a spoiler for those interested in bringing real change to the broken Maryland political system."

A spokesman for Sobhani said the campaign's internal polling shows a tighter race. He said he suspects the number of voters who are undecided or willing to change their mind is much higher.

"Broad dissatisfaction with both parties leads us to believe that voters will decide in ways down ballot that surprise the pundits this year," campaign spokesman Sam Patten said in an email.

Although Bongino has long been considered a long-shot in deeply Democratic Maryland, his campaign has shown some signs of momentum in recent weeks. He has raised more campaign cash recently than Cardin, a difficult feat for a newcomer. But despite concerns over the economy and an overall dissatisfaction with Congress, Bongino has been unable to completely nail down voters within his own party, the poll shows.

Supporters credit Bongino for energizing the state's Republicans — and many speculate about whether he will run for statewide office again in 2014 if he loses this year. But only 58 percent of Republicans said they will support him for Senate, while 18 percent fled to Sobhani. By contrast, three in four Democrats say they will back Cardin.

Cardin, meanwhile, has his own set of weaknesses. He is not performing as well in Maryland as President Barack Obama and he is not as well known as the state's senior lawmaker, Sen. Barbara A. Mikulski. But those issues are not new and they do not appear to be a major obstacle for re-election.

Sobhani, who ran as a Republican candidate for Senate in 1992 and 2000, entered the race in September after turning in 77,000 signatures to the state Board of Elections. Since then, he has paid for millions of dollars in television advertising in the Baltimore and Washington media markets — almost all of it his own money.

The poll has a margin of error of plus or minus 3.5 percentage points.

"Senator Cardin continues his outreach to voters across the state, focusing on his strong record of accomplishments on behalf of all Marylanders, especially his support of small businesses and job growth," Cardin campaign spokeswoman Sue Walitsky said in a statement.

john.fritze@baltsun.com

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