Sen. Benjamin Cardin (D) begins the election year with good marks from a bare majority of all Marylanders and a more sizable share of his fellow Democrats, according to a new survey.

The Gonzales Research & Marketing Strategies poll of Maryland released Wednesday shows that 51 percent of registered voters in the state approve of the job Cardin is doing, while 32 percent disapprove and 16 percent have no opinion. That puts him just below President Obama and Gov. Martin O’Malley, who received 55 and 53 percent approval ratings, respectively.

Cardin is considered a favorite to win a second term in 2012, given the strong Democratic bent of Maryland and the presence of Obama atop the ticket to drive turnout. A total of 10 Republicans have filed for the seat, including ex-Secret Service agent Daniel Bongino and former Pentagon and Justice Department lawyer Richard Douglas.

Cardin also faces opposition from several candidates in the April 3 Democratic primary, most notably from state Sen. C. Anthony Muse. The Gonzales poll finds that Cardin scores a 68 percent approval rating among Democrats, which means, the survey firm suggests in a memo, ”he would be difficult to defeat in a primary.”

The Gonzales poll’s findings are similar to those of a May 2010 Washington Post poll of Maryland, which gave Cardin an approval rating of 48 percent among all registered voters and 65 percent among Democrats.