Former McCain aide: Sarah Palin's Trump endorsement a "big lose" for Ted Cruz

Former McCain campaign manager on Palin endor... 03:32

Rick Davis, the campaign manager for 2008 GOP nominee John McCain, said Texas Sen. Ted Cruz is the loser in former Alaska Gov. Sarah Palin's decision to endorse businessman Donald Trump for the 2016 GOP nomination.

"You win every day or you lose every day in a campaign at this stage down to the wire. And it was a big win day for Trump and a big lose day for Cruz," Davis said on "CBS This Morning."

There's a "battle for the dwindling Carson vote," he said, which is why both Trump and Cruz are pushing so hard to build support from evangelicals and other groups that like former neurosurgeon Ben Carson. He still commands between 8 and 10 percent of the vote in many polls of likely Republican caucus goers.

Sarah Palin endorses Donald Trump 02:02

That's not to say Palin's endorsement will necessarily do much for Trump outside of Iowa, Davis said.

"I think everywhere else in the country, you know, people are scratching their head when they wake up this morning and saying, 'What is he thinking?'" Davis said. "But I think he's made a bet that if he can win in Iowa, he has a shot at ... running the table."

Whether that strategy works remains to be seen. Davis explained that in the old schedule, a candidate that won Iowa and New Hampshire had a huge amount of momentum and would likely be able to sweep up the nomination. Now, he said, there's a two week-period after the South Carolina primary where delegates are awarded proportionally, rather than all going to the winner. That makes it harder for one candidate to break away from the pack.

Davis said he sees three major segments of voters: The "outsider" supporters who like Trump and "are really happy with what they've got." That's about a third of the vote. Another third is "movement conservatives" who are loyal to Cruz. The final third is made up of establishment Republicans - but their support is spread among five or six candidates.

"As that consolidates ... you've got three trains that are running down the track and if they continue to win a 30, 30, 30, I don't know how you get to a point where you have one person you know with the necessary delegates to be the presumptive nominee," he said.