POTOMAC, Md. (AP) -- Democratic Sen. Ben Cardin has won re-election to the U.S. Senate, defeating a Republican and a well-financed independent.

Based on exit polling Tuesday, Cardin defeated Republican Dan Bongino and independent Rob Sobhani (seh-BONN'-ee).

Cardin was first elected to the Senate in 2006 after a long career in the House of Representatives.

Bongino is a former Secret Service agent and political newcomer. Sobhani had previously run unsuccessful campaigns as a Republican and spent more than $4 million of his own money to flood the airwaves and finance his run this year as an independent.