GOP candidates face off in fourth debate

Eight Republican presidential candidates slugged it out over immigration, war in Syria, military spending and flat-tax proposals at a Wisconsin debate Tuesday night while sharpening attacks on one another with less than three months before the first primary.

Real estate mogul Donald Trump and Sen. Ted Cruz of Texas pushed hard for cutting off illegal immigration and deporting undocumented workers already in the country, while former Florida Gov. Jeb Bush and Ohio Gov. John Kasich blasted the idea as unworkable, "silly" and damaging for Republicans in the general election.

Sen. Rand Paul of Kentucky blasted his rivals, especially Sen. Marco Rubio of Florida, charging they would expand military spending with no way to pay for it. That prompted sharp rebuttals -- cheered by the debate audience in Milwaukee -- on why the American military must be "bigger and better."

Retired neurosurgeon Dr. Ben Carson, leading in some polls, didn't answer questions about the veracity of his autobiography, deflecting them by saying former Secretary of State Hillary Rodham Clinton, the front-runner for Democratic presidential nominee, lied about the Benghazi attacks. Carson took a milder tone during most of the contentious policy debates of the night.

Paul, Cruz and Carson called for a flat tax while pushing back against questions about whether the plan would cause deficits.

Trump drew fire from most of his rivals for asserting the United States should sit back and let Russia help drive ISIS out of Syria, and then later try to remove Syrian President Bashar al-Assad from office.

The sharper critiques among the eight candidates on stage reflected the narrowing window between the 2015 debates and the pending Iowa caucuses and New Hampshire primary.

After most of the candidates voiced opposition to raising the minimum wage (including Carson, who months earlier favored doing so), the Fox Business Network debate panel put them on the spot about immigration -- one area of clear differences.

"We will have a wall. The wall will be built. It will work," Trump said, repeating his proposal about building a wall along the southern border, making Mexico pay for it and deporting 11 million people in the United States to stem undocumented immigrants.

That remark brought sharp rebukes from Kasich and Bush.

"Come on, folks, we all know that you can't pick them up and ship them across the border," Kasich said. "It's a silly argument."

Trump replied with an insult: "I built an unbelievable company that's worth billions and billions of dollars. I don't have to listen to this man."

But Bush jumped in, saying Trump's idea would "tear communities apart" and hand the election to the Democrats.

"They're doing high-fives in the Clinton campaign when they're hearing this," Bush said.

The comment triggered a retort from Cruz, a conservative trying to woo the conservative base, especially in Iowa. "If Republicans join Democrats as the party of amnesty, we will lose," he said.

The personal critiques continued on tax plans.

Paul fired at Rubio: "How can you be conservative if you keep promoting programs you can't pay for," singling out expanded military spending.

Rubio responded by calling Paul a "committed isolationist" and saying, "I know that the world is a safer place when America is the strongest military power in the world."

Paul zinged Trump for alluding to China while blasting the Trans-Pacific Partnership trade pact. "China's not in the TPP," he said, hitting a Trump weakness: command of policy details.

Trump, a GOP front-runner before Carson's rise in recent polls, also was criticized by Bush for saying the United States should let Russia take care of Syria for now. Trump said of Russian President Vladimir Putin: "I got to know him very well, because we were both on '60 Minutes.' We were stablemates that night."

Businesswoman Carly Fiorina, calling for a hard line against Putin, said, "Mr. Trump fancies himself a very good negotiator. . . . so Mr. Trump ought to know that we should not speak to people from a position of weakness."