PHILADELPHIA — Vice President Joe Biden is questioning Donald Trump’s “moral center” as a result of the Republican presidential candidate’s comments about America’s housing collapse.

Biden told a Hillary Clinton rally at Drexel University in Philadelphia on Tuesday that Trump had bragged at Monday’s presidential debate about profiting from the failed housing market.

The vice president said Trump “is a guy who said it was good business for him to see the housing market fail.”

Biden added, “What in the hell is he talking about?”

At the debate, Clinton said Trump had rooted for the housing collapse in 2006 because he saw it as a way to go in and make money. Trump responded, “That’s called business, by the way.”

Biden said Trump “brags about gaming the system and bankruptcy.”