What would it take for Trump to win?

Republicans play the delegate game 02:11

WASHINGTON -- In campaign for the nomination, the two top Republican presidential candidates are in a pitched battle for delegates. Donald Trump needs less than 500 to win the party's nomination. Ted Cruz is doing everything he can to prevent that.

Paul Manafort, Donald Trump's new campaign chief, promised that the billionaire developer will win the GOP nomination outright. But Cruz has narrowed Trump's advantage with a win in Wisconsin and delegate grabs in Colorado, Louisiana and North Dakota.

This year's contest for Republican delegates has been compared with the 1976 contested Republican convention when Ronald Reagan challenged President Gerald Ford. CBS News

"The reality is this convention process will be over with sometime in June, probably June 7th and it'll be apparent to the world that Trump is over the 1,237 number," he said.

That's the magic number to secure the nomination without a floor fight at the July convention.

"You've got to understand what the game is. If the game is a second, third or fourth ballot, then what he's doing is clever. But if there's only one ballot, what he's doing is meaningless," Manafort said.

This all has the makings of the 1976 contested Republican convention. That year, Ronald Reagan challenged President Gerald Ford.

"At that point, the delegate ceases to be an extra on a four-night miniseries where he or she is supposed to applaud at the right time and they become real agents of the party," said Frank Donatelli, who was a youth organizer for Reagan.

Ford kept delegates in line by offering, among other things, rides aboard Air Force One and seats at state dinners.

The laws governing incentives to delegates are murky, something the candidates this year could exploit. And after a first ballot, most delegates can switch allegiances.

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"Could you offer transportation or room and board or something?...I mean there's a lot of ways to persuade uncommitted delegates," Donatelli said.

Trump could offer flights aboard his helicopter or luxurious private jet, a weekend at Mara Lago Club or a tee time at trump national. But ideology sometimes trumps trips or presents and for conservatives, Cruz might be more attractive than swag