And big divides they were…..

Deep differences among the candidates over everything from immigration to the use of military force were exposed at Tuesday’s Republican primary debate, where front-runners Donald Trump and Ben Carson often had to cede the spotlight to a full stage of spirited competitors.

Even Jeb Bush, who has struggled for airtime during past face-offs, was able to elbow his way into the fray, taking shots at President Obama’s economic record and Trump’s immigration plan.

“They’re doing high fives in the Clinton campaign right now when they hear this,” Bush said, of Trump’s call to deport millions.

Whether Bush, the former Florida governor who has steadily slid in the polls since losing his summer front-runner status, can regain momentum is an open question. And he was hardly alone among the middle-tier candidates asserting their policies on stage at the Fox Business Network/Wall Street Journal debate in Milwaukee.

One of the biggest wedges was over the U.S. military.

Kentucky Sen. Rand Paul held his ground in vociferously calling for reining in the military budget and avoiding foreign military interventions. For this, he drew sharp rebukes from Florida Sen. Marco Rubio, former HP CEO Carly Fiorina and others.

“I know that Rand is a committed isolationist. I’m not,” Rubio said.

Paul countered that spending on defense is driving up the debt and making America “less safe.”

“I want a strong national defense, but I don’t want us to be bankrupt,” he said.

This snowballed into a heated debate over Russia’s mounting intervention in the Middle East.

When Trump suggested the U.S. cannot be the world’s policeman, Bush said “he is absolutely wrong on this” and the U.S. needs to be the “world’s leader.”

Fiorina said both Trump and Paul should know that “we should not speak to people from a position of weakness.” In a stand-out moment, Fiorina rattled off her plans for countering Putin’s profile, including rebuilding the missile defense system in Poland, launching military exercises in the Baltic states and perhaps putting thousands of troops in Germany.

The U.S. needs to have the “strongest military on the planet and everyone has to know it,” she said.

“You can be strong without being involved in every civil war in the world,” said Paul, not backing down.

When Fiorina tried to interject, Trump scolded her – saying, “Why does she keep interrupting everybody?” – but was booed by the audience.

Rubio added that Putin is a “gangster” who understands “only geopolitical strength.”