Reality TV star and real estate mogul Donald Trump is endorsing Republican Richard Mourdock in the Indiana Senate race.The billionaire conservative has become a controversial figure for questioning President Obama's birth certificate while he briefly flirted with a White House bid. For the most part, Trump has been lampooned for embracing the so-called "birther" movement and observers have criticized his remarks as a publicity stunt.On Wednesday afternoon, Trump Tweeted: "Richard Mourdock—a very good man running for the Senate in Indiana. Hopefully, he will win!"Mourdock is running against Indiana Congressman Joe Donnelly in the general election.Indiana Democrats wasted little time before pouncing on the endorsement."It's no shock that Tea Party Senate candidate Richard Mourdock got the support of America's biggest birther," says Democratic Party spokesman Ben Ray. "After all, Donald Trump's catchphrase is 'you're fired,' which is what Mourdock tried to tell more than 100,000 Hoosiers when he sued to liquidate Chrysler."The Mourdock campaign has not yet responded to our request for comment.