Donald Trump savaged for immigration policy at GOP debate: 'We can’t ship 11 million people out of this country…children will be terrified'

'We all know we can’t pick them up and ship them across the border, it is not a serious argument,' said John Kasich

The eight leading Republican candidates for president navigated huge fissures separating them on several fronts at a frosty and fractious debate in Milwaukee, Wisconsin, last night, not least with starkly diverging visions on foreign policy and on how they would like to see Americans taxed.

Donald Trump, who drew boos from the audience when he scolded Carly Fiorina for “interrupting everybody”, declared that he welcomed President Vladimir Putin’s intervention in Syria. “If Putin wants to go in and knock the hell out of Isis I am all for it, one hundred per cent,” he said.

Jeb Bush, the former governor of Florida, who came to the night under intense pressure to improve on past debate performances, turned on Mr Trump and said he was approaching foreign policy with a “board-game mentality”.

One of the sharpest exchanges of the night, which marked the fourth debate between Republican hopefuls, came when Senator Rand Paul tried to suggest that Senator Marco Rubio could not be a conservative and at the same time fail to limit spending on the American military. It got him a quick reply.

Parts of the night even turned into a debate on how big the US military should be. Branding Mr Paul an isolationist, Senator Rubio, whose mantra is that he will be the president of the 21st Century, asserted: “I know that the word is a stronger and safer place when we are the strongest military power in the world.” That and the other lines from Mr Rubio drew some of the strongest applause of the night.

The leading candidates take the stage in Milwaukee. Morry Gash/AP (Morry Gash/AP)

Both Mr Trump and Ben Carson, the retired neurosurgeon, who together continue to lead the polls, evoked generals they had “recently talked to” to underpin their foreign policy comments. Mr Carson said the solution on Isis was to make them “look like losers” and one way to do that would be take the oil fields in Iraq from their control, implying that he would use US troops to do it.

Leaving Mr Trump aside, some candidates vied with one another to promise to be toughest with Mr Putin. While Mr Rubio called the Russian leader a “gangster”, Ms Fiorina vowed to build new missile defence systems “under his nose” in Poland and return thousands of US soldiers to Germany, not to “start a war,” she said, but to show Moscow the US “is serious about defending its allies”.

Perhaps it was Mr Trump who suffered the worst incoming fire at the debate that was jointly sponsored by the Fox Business Channel and the Wall Street Journal. John Kasich, the Governor of Ohio, with some backing from Mr Bush, ripped into the property magnate for continuing to suggest that he would build a wall along the border with Mexico and deport 11 million people living in the US illegally.

“We all know we can’t pick them up and ship them across the border, it is not a serious argument, not an adult argument…we can’t ship 11 million people out of this country…children will be terrified,” Governor Kasich said. Mr Trump grumpily returned: “I don’t have to hear from this man.” Mr Bush argued that Mr Trump’s deportation pledge meant Hillary Clinton was doing “high fives” in her camp.

While on taxation there was a consensus that Americans should be paying less of them, there was little agreement on how to set about that with three – Senators Cruz and Paul as well as Mr Carson – seeking a flat tax solution (with Mr Cruz also seeking to eliminate the Internal Revenue Service entirely) and everyone else offering less radical plans for lower taxes and a smaller tax code.

After suffering a battering over the last several days over details of his biography, Mr Carson seemed to find a smoother groove on the stage. He tried and perhaps succeeded in dispensing with the controversies fairly quickly. “I have no problem being vetted, what I do have a problem with is being lied about and putting it there as if it was true,” he said.

Senator Cruz, the Tea Party favourite from Texas, skirted close to mimicking the famous “oops” disaster that befell the former Governor of Texas, Rick Perry, four years ago when he pledged to eliminate three federal agencies in Washington but could remember only two of them. Mr Cruz did two better and said he would get rid of five. And he named them: the IRS, Energy, Commerce, Housing and Urban Development and Commerce. Yes, he said Commerce twice.