"I do think he'll wind up, you know, wind up having to commit more troops there," Christie told CNN's Jake Tapper. He added, "When you sit and talk to him about facts, he listens, absorbs and alters his view. I think that's what we want from a politician."
In March, Trump said at a CNN-hosted debate that the US has "no choice" but to defeat ISIS and said he was "hearing" that as many as 30,000 troops might be necessary
to achieve that goal. He then told CBS News on Sunday that he would declare war on the terrorist group and send "very few" US troops
to combat them.
Christie said he expects Trump to become more aggressive after he delivers his convention speech Thursday. He added that Trump is "strong" about increasing US overseas intelligence capabilities and said the Republican nominee would be "consistent in his rhetoric on the nature of the threat."
The New Jersey governor also said he talked with Trump Tuesday but did not talk about Melania Trump, whose speech on Monday plagiarized passages from a 2008 address delivered by First Lady Michelle Obama. He said he expected to talk about Melania's speech with Trump later Wednesday. A Trump organization staffer took responsibility for the incident Wednesday.
"I don't know what the dynamic is that's going on within the Trump household right now, but I know Melania very well," Christie said. "And I know Melania is a private person, really intelligent, really cares about Donald, loves him and loves her son."
Christie said the speech controversy has become demeaning for her.
"Now there's all this stuff from a speech that she probably didn't want to give in the first place, that is demeaning to her even by extension," he said.
He added, "It would make me enormously uncomfortable if a member of my staff had done that to my wife."
The public, Christie said, needs to understand that it is hard for many families when they are thrust into politics the way that the Trump family has been. He said the campaign staff, the family and the candidate often form a political "love triangle" that needs to be balanced.
"I suspect when I speak to him later today that I'm going to hear a big personal dynamic that's part of this story too because it involved his wife," Christie said. "And I think to underestimate how that impacts the way you make decisions, the rapidity of your decisions, and the nature of them, is to give less of an understanding than there really needs to be to that triangle."
The New Jersey governor also said he hoped Texas Sen. Ted Cruz would finally endorse Trump in his speech Wednesday night -- something he said Cruz had promised he would do.
"I hope Ted Cruz gets up tonight when he speaks tonight and keeps his word, endorses Trump," Christie said. "He was kissing Donald's rear end for first six months of the campaign. They did rallies together on Capitol Hill. Seriously. They don't realize Donald isn't a politician. He thought Ted really meant it."