GOP frontrunner Donald Trump smacked down Sen. Marco Rubio when he rushed to Jeb!'s defense and tried to claim that his brother kept us safe during this Saturday's CBS GOP debate: Donald Trump Goes After George W. Bush For Not Keeping America Safe On 9/11:

Donald Trump and Jeb Bush rumbled Saturday night over whether or not George W. Bush did enough to keep America safe during his presidency. In the process, Trump bulldozed through GOP orthodoxy on George W. Bush's record on 9/11, calling him out for not keeping America safe.

"The World Trade Center came down during your brother's reign. Remember that," Trump said after Jeb Bush said he was sick and tired of Trump always attacking his family.

"That’s not keeping us safe," Trump said.

Rough transcript below (h/t Sarah P.):

RUBIO: I just want to say on behalf of me and my family that I think god all the time that it was George W Bush in the White House on 9/11 and not Al Gore. I think you can look back in hindsight and say a couple of things - but he kept us safe. And not just that he kept us safe, no matter what you want to say about weapons of mass destruction, Saddam Hussein was in violation of UN resolutions, open violation. and the world wouldn't do anything about it. George W. Bush enforced what the international community refused to do and he kept us safe. I am forever grateful to what he did.

TRUMP: How did he keep us safe when the World Trade Center (mumbling). I lost hundreds of friends. The World Trade CEnter came down during the reign of Bush. He kept us safe? That's not safe. That is not safe.

RUBIO: World Trade Center came down because Bill Clinton didn't kill Osama bin Ladin when he had the chance to kill him.

TRUMP: By the way, George W. Bush had the chance also and he didn't take the advice of his CIA.

BUSH: I am not going to invite Trump to the rally in Charleston on Monday afternoon.