Will Trump's 9/11 Taunt Against the Bushes Backfire?

Republican U.S. presidential candidate and businessman Donald Trump speaks at the Republican U.S. presidential candidates debate sponsored by ABC News at Saint Anselm College in Manchester, New Hampshire, on February 6, 2016. Trump attacked Jeb Bush for his brother’s “failure” to keep America safe at the more recent debate. Carlo Allegri/Reuters

This article first appeared on the London School of Economics site.

Karl Rove, George W. Bush's former political adviser and electoral campaign strategist, claimed that the best way to defeat your opponents was to attack their strengths—to turn their electoral advantage with voters (e.g., war heroism, Hollywood stardom) into a political liability.

This is precisely what Trump did in last weekend's Republican debate in South Carolina, the site of the first southern primary this coming Saturday.

Trump attacked Jeb Bush for his brother's "failure" to keep America safe. George W. Bush was responsible for 9/11, Trump claimed. It happened on Bush's watch and that, Trump implied, makes the former president accountable. Doubling down, Trump also said he would have impeached Jeb's brother for invading Iraq.

It was a stunning rhetorical turn in a campaign that has had no shortage of them. It's one thing for a Democrat to challenge a Republican's bone fides on national security, though it happens far less frequently than one might think. But it is another altogether for a Republican to attack a fellow Republican for being incompetent on national security. That's what Trump did.

Not surprisingly, it has caused a huge stir within the Republican camp. Many Republicans accept that the invasion of Iraq was a mistake. But blaming George W. Bush for 9/11 has been off limits—until now. Why did Trump do it and will it backfire?

Karl Rove gave us the answer to the first question. Trump is going in for the kill in South Carolina. If Jeb Bush is soundly defeated there, in a conservative state that backed his brother and his father, for that matter, it is hard to see how he survives politically. This is Bush, not Trump, country.

Is Trump's campaign tactic risky? Absolutely, but it may work.

In a South Carolina poll released February 16, Trump is still leading his rival with 35 percent of the vote. Significantly, the poll was conducted after last weekend's heated GOP debate.

If Trump's numbers do hold up after launching such a blistering attack on a core feature of the Republican brand (national security), hold on to your seats.

Peter Trubowitz is professor of international relations, and director of the London School of Economics 's U.S. Centre. This article gives his views and not the position of USAPP–American Politics and Policy, nor the London School of Economics.