Donald Trump. ABC/screengrab Real-estate mogul Donald Trump apparently thinks the time has come for former Florida Gov. Jeb Bush (R) to end his presidential campaign.

"Jeb is not a man that's going to make it, OK? He's wasting his time. He's wasting a lot of money," Trump said during a Tuesday interview on "Good Morning America."

Bush, once labeled a Republican front-runner, has sagged in the polls as outsider candidates like Trump have surged.

The former governor still has a monstrous super PAC supporting his candidacy, but the Bush campaign nevertheless had to implement across-the-board pay cuts in an attempt to right the ship.

Trump encouraged Bush to copy Wisconsin Gov. Scott Walker (R), who ended his presidential campaign in September when it faced a sudden cash crunch.

"Jeb's a nice guy. He's a stiff, OK? He's a nice guy. He doesn't have a chance. He ought to do what Walker did," Trump said.

Asked if Bush should drop out, Trump replied: "Absolutely."

"He has no chance. He's got money but the money's not going to do it. And he's been branded as a 'low-energy' person," Trump added, repeating the insult he frequently uses against Bush. "I don't know who branded him. I can't imagine."

Trump's trash-talk followed "Good Morning America" playing a clip from a Bush campaign speech the day before. In that speech, Bush took some not-so-subtle shots at Trump.

"The solution won't be found in someone who has never demonstrated the capacity to implement conservative ideas," Bush said. "And you can't just tell Congress, 'You're fired!' And go to commercial break."