Amid a series of bloody and troubling episodes in Afghanistan that have inflamed Afghan opinion against the United States, Rick Santorum and Newt Gingrich are now calling for a reassessment of American policy there — suggesting that it may be time to withdraw troops sooner than the Obama administration has planned.

Their views echo recent polls that show public support for the Afghan war has fallen sharply among voters of all parties.

In an interview Monday on NBC’s “Today” show, Mr. Santorum, long among the most hawkish Republican candidates on Afghanistan, signaled that it was time to review America’s options. One option, he said, was to leave even sooner than called for in the timeline laid out by the Obama administration, which would turn over security to Afghan forces by 2014 and end the leading combat role for American troops by next year.

“We have to either make the decision to make a full commitment, which this president has not done, or we have to decide to get out, and probably get out sooner,” Mr. Santorum said.