Analysis: New Fights Emerge as Candidates Try Ignoring Trump

Confronted with the durable phenomenon known as Donald Trump, the leading Republican presidential candidates tried a new tack Tuesday night: ignore him.

Trump didn't go anywhere, of course. Attacks did flow in from candidates who found themselves farther from center stage than ever -- including, notably, Jeb Bush.

But it's as if his front-running status is so familiar that his rivals for the most part chose not to fight him, as the race settles into its lanes. At a tense time in the nation, attention turned to once familiar -- even old-school -- arguments inside the Republican Party.

A scattered debate that focused almost exclusively on foreign policy and national security revealed tension between the GOP's hawkish and libertarian strains, its Senate and gubernatorial leaders, and two first-term senators who may well be the last Republican candidates standing.

The most tense exchanges pitted Ted Cruz against Marco Rubio, the onetime allies who now see themselves as each other's most serious rival. Rubio attacked Cruz for supporting an end to surveillance programs and limiting defense spending, while Cruz hit Rubio hard over immigration.

"We are now at a time where we need more tools, not less tools," Rubio said. Later, he added: "You can't carpet-bomb ISIS if you don't have planes and bombs to attack them with."

Cruz accused Rubio of distorting his record, and -- a harsher charge -- empowering the Obama administration's mission.

"One of the problems with Marco's foreign policy is he is far too often supported Hillary Clinton and Barack Obama undermining governments in the Middle East that have helped radical Islamic terrorists," Cruz said.

It left Chris Christie open to argue a basic point -- that the fights on stage probably weren't registering with voters who are jittery in the wake of world and national events.

"Let's talk about how we do this and not which bill which these guys like more. People don't care about that," Christie said.

The anti-Trump charge was left mostly to Bush, whose migration away from center stage has been accompanied by a desire to fight with the man who still occupies it. Bush attacked Trump for a lack of "seriousness," noting snidely at one point that he was giving him "a bit of your own medicine."

"Donald is great at the one-liners. But he's a chaos candidate. And he'd be a chaos president," Bush said, in a line worked up sufficiently in advance so that his campaign had a Website with that label ready to go.

Trump brushed the attacks aside, taunting Bush over his poll numbers and with now-familiar rejoinders.

"I know you're trying to build up your energy, Jeb, but it's not working," he said.

"You started off over here and moving over further and further," Trump said later, referring to Bush's position on the stage. "Pretty soon you're gonna be off the end."

With voting drawing near, the candidates are choosing the battles that work for them. Cruz and Rubio will claw at each other's records; Christie, John Kasich, and Carly Fiorina will post up against the candidates who work in Washington; Bush is now positioning himself as the main anti-Trump force in the race.

The last Republican debate of the year left the GOP where it's been at the start of this wild, six-month run. Trump may fade, but it looks increasingly likely that it won't be what the other candidates say about him that makes it happen.

Toward the end of the debate, Trump even felt generous toward Cruz -- now his closest rival in Iowa, and perhaps nationally.

"He has a wonderful temperament. He's just fine - don't worry about it," Trump said. "You better not attack."