Bush's trouble started with what should have been a very easy interview on Monday night with Megyn Kelly, a star on the Fox News network, an outfit that is traditionally extravagantly friendly to the Bush family and the Republican Party. Jeb Bush in Puerto Rico last month. Credit:AP "On the subject of Iraq, very controversial, knowing what we know now, would you have authorised the invasion?" Kelly asked. "I would have and so would have Hillary Clinton, just to remind everybody, and so would almost everybody that was confronted with the intelligence they got," Bush responded, to Kelly's apparent surprise. "You don't think it was a mistake?" she pushed.

"In retrospect, the intelligence that everybody saw, that the world saw, not just the United States, was faulty," Bush answered. At number two, Hillary Clinton is closing in on Angela Merkel. Credit:AP This was widely viewed as a preposterous answer. While Republicans do not readily apologise for George W. Bush's war in Iraq, they rarely seek to defend it. George H.W. Bush in 2013. Credit:Reuters

It did not take long for his answer to come under fire from the right. "No, Hillary wouldn't," said the right-wing talk show host Laura Ingraham. "[She] wouldn't authorise the war now, if she knew what she knew now then. No, of course not!" George W. Bush with his father, George H.W. Bush in 2009. Credit:AP Even though the question is purely hypothetical, Ingraham continued: "You have to say 'No' to that; you can't say, 'Yes, I'd still would have gone into Iraq.' "Or if you do, then there has to be something wrong with you. You can't think going into Iraq now, as a sane human being, was the right thing to do. That's like you have no ability to learn from past mistakes at all."

The Bush family in 1964. George H.W. Bush sits on couch with his wife Barbara and their children. George W. Bush sits at right behind his mother. Behind the couch are Neil and Jeb Bush. Credit:AP Conservative columnists like Daniel Larison of the American Conservative and Byron York of the Washington Examiner soon piled on. York, in a piece entitled Jeb Bush's Disastrous Defence of the Iraq War, noted that not even George W. Bush casts the war in that light. In his memoir Decision Points, the former president describes the intelligence that lead to the war not as "faulty" but as "false", York notes. The invasion was, W. Bush wrote, a "massive blow to our credibility - my credibility - that would shake the confidence of the American people".

"I had a sickening feeling every time I thought about it," he wrote. "I still do". Soon other contenders for the Republican nomination had distanced themselves from the war, though they avoided criticising Jeb Bush by name. Rand Paul told CNN on Wednesday: "You know, I think it's a really important question and I don't think it's just hypothetical. "Because we seem to have a recurring question in the Middle East whether or not it's a good idea to topple a secular strongman or secular dictators and what happens after that." "I think even at the time invading Iraq was a mistake and I thought the war, even at the time, was a mistake, given the intelligence. Everybody needs to be asked - all the Republicans should be asked, did you and do you support Hillary's war in Libya? And so I think as these questions get asked, we will get to the answer of who Republicans want to lead the country, who do Americans want to lead the country."

Kelly herself lobbed the same question to the hawkish Texas senator Ted Cruz on Tuesday: knowing what we know now, would you have invaded? "Of course not," he responded. The New Jersey governor Chris Christie, chimed in: "I don't think you can honestly say that if we knew then that there was no (weapons of mass destruction), that the country should have gone to war." The Ohio governor John Kasich told The Columbus Dispatch: "There's a lot of people who lost limbs and lives over there, OK? "But if the question is, if there were not weapons of mass destruction should we have gone, the answer would've been no."

Habitual critics of the Republican Party were far less gentle. "When an Iraq War question starts with 'knowing what we know now,' . . . 'hell yes I'd still do it' is not an acceptable response," said the Daily Show's Jon Stewart. "Sure I'd get on the Titanic again!" he added. "I mean at the time, it had a terrific buffet." Perhaps what is most surprising about Jeb Bush being wrongfooted on this question is that he must have prepared for it. His surname is at once one of his greatest assets and most significant burdens. As the son and brother of former presidents, he has inherited a nationwide network of supporters, staff and donors unrivalled in his party.

But is has left him with his brother's disastrous legacy and a thorny political problem. It would be unseemly for him to distance himself too much from his brother, but the extent to which he has aligned himself with the W. Bush legacy has raised eyebrows. He counts among his advisers Paul Wolfowitz, one of the architects of the war, and just last week Jeb Bush told a meeting with high-powered investors that his brother was his most influential counsellor on Israel and Middle East policy, the Washington Post has reported. According to the Post, the response in the room was mixed. One said his comments were received well, but another said: "I started looking around and wondering if people were recording it. It was jarring. If video of it got out, it'd be devastating."

Perhaps aware that not being able to answer such a question at this point in the race veered towards political malpractice, on Tuesday Bush began ducking the question entirely. Asked to clarify the comment by a voter during an event in Nevada on Wednesday, Bush reportedly replied: "If we are going to get into hypotheticals, I think it does a lot of disservice for a lot of people who sacrificed a lot." Just as though a political campaign was not one long answer to the hypothetical question "What would you do?".