But now, with the Afghanistan war tumbling to all-time lows in public support, it has become difficult for Romney to contrast his policies with Obama’s without advocating a slower withdrawal — and a longer war.

Obama has blunted some of the GOP criticism by saying that he will not announce any more troop withdrawals — the most frequent GOP point of attack — until after the surge troops leave this fall.

“[Romney’s] got no place to go on this, and I think if he’s smart he’ll be quiet,” said Lawrence Korb, a former senior Pentagon official and senior fellow at the liberal-leaning Center for American Progress. “The American people, even the Republicans, have turned against the war. They think it’s gone on long enough.”

Even critics of Obama’s Afghanistan policies acknowledge it’s unlikely to become a liability for him.