Whichever candidate wins the US presidential election in November, either the president or vice-president will have a son fighting in Iraq. If the Republicans win, then the two most powerful people in America will each have a son on the battlefield.

The almost simultaneous deployment of three candidates’ sons has pushed the Iraq war back on to the political agenda, but it has also presented the Pentagon with a “Prince Harry” dilemma: whether to afford these soldiers special protection and whether they should be exposed to danger at all, given the huge potential political consequences.

John McCain, the Republican candidate, has deliberately not emphasised the military service of his teenage son, Jimmy, who heads back to Iraq for a second tour of duty later this year, but Sarah Palin, his running-mate, has repeatedly emphasised her role as a “military mom”.

Pointing to Mr McCain’s extraordinary war record in Vietnam, Mrs Palin told a rally in Missouri this month: “I’ll tell you, as a mother of one of those troops, that is exactly the kind of man I want as commander-in-chief.”

The Democrats, sometimes accused of lacking patriotism for opposing the war, can point to the imminent deployment of Beau Biden, the son of the Democratic vice-presidential candidate Joe Biden, to burnish their military credentials.

Prince Harry was brought back from Afghanistan when his presence there was made public, and American military officials are acutely aware that each of the three men could become a target, with the potential to transform the presidential race.

James Currie, a retired colonel and professor at the National Defence University, argues that presidential and vice-presidential children should not remain in a warzone.

“Can you imagine the propaganda victory if al-Qaeda or some organisation over there were to injure or kill or, heaven forbid, capture the son of a president or a vice-president? I cannot imagine what that would be,” he told NPR Radio last week.

As infantrymen, Track Palin and Jimmy McCain are likely to be in particular danger. The Pentagon insists that they will receive no special treatment and refuses to discuss any special contingency plans in the event of one being killed or injured.

The Secret Service provides protection to the children of the president and vice-president but the agency has never faced the task of doing so for family members serving in a warzone.

The triple deployment marks an important demographic and cultural shift in American political life.

In recent presidential elections, debate has centred on whether the candidates themselves served in the military, most notably in Vietnam, but with the Iraq war, the focus has shifted to whether they have seen their children go to war — a far more traumatic process, in many ways, but one that is now shared by thousands of American families.

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