Sen. Benjamin Cardin (D) will formally launch his reelection campaign Sunday, exactly one year before Marylanders go to the polls to decide whether to grant him a second term.

Cardin’s decision to run again has been a foregone conclusion, but he will make the step official with a 3:30 p.m. speech at the Baltimore Museum of Industry. He begins his bid as a clear favorite, given Maryland’s strong Democratic lean and his large campaign war chest.

“The last few years have been tough times and there is still much work to be done to get people back to work and to restore our growth economy,” Cardin said in a release announcing the event.

State Sen. C. Anthony Muse (Prince George’s) announced in September that he was considering a challenge to Cardin in the Democratic primary, contending that no one in the Senate — including Cardin — was adequately addressing issues like education and “bringing our soldiers home” from wars abroad.

On the Republican side, former Secret Service agent Daniel Bongino has been the most active and aggressive candidate, speaking often about his unusual career arc in free media appearances. (Bongino testified this week in the federal trial of a man accused in a rental car fraud scheme, a case he investigated when he was in the Secret Service.)

As of Sept. 30, Bongino had $31,000 in his campaign account, while Cardin had $2.3 million in the bank.

Former Queen Anne’s Commissioner Eric Wargotz, who was beaten soundly in 2010 by Sen. Barbara Mikulski (D), and Del. Patrick L. McDonough (Baltimore County) are also considering runs for the GOP nomination to face Cardin.

A Washington Post poll released in May 2010 found that 48 percent of registered voters in Maryland approved of the job that Cardin was doing, 21 percent disapproved and 31 percent had no opinion. Cardin had a 65 percent approval rating among Democrats.