As President Obama called Wednesday night for scaling down troop numbers in Afghanistan over the next year, differences over how to approach the conflict emerged among GOP presidential hopefuls, with some calling for a faster withdrawal and others arguing for a more conditions-based drawdown.

The contrast among 2012 Republican candidates reflects a change in the party’s hawkish orthodoxy, unease over spending and crumbling support for the war. The most recent poll shows that nearly three quarters of Americans believe a substantial number of troops should come home this summer.

Jon M. Huntsman Jr., looking to distinguish himself from the rest of the field, has zeroed in on the cost of the conflict, staking out a position that is more in sync with a war-weary public yet breaks with Obama over the number of troops on the ground.

Huntsman said the nation faces “a generational opportunity to reset our position in the world in a way that makes sense for our security as well as our budget.”

“Now it is time we move to a focused counter-terror effort which requires significantly fewer boots on the ground than the President discussed tonight,” he said in a statement. “We need a safe but rapid withdrawal which encourages Afghans to assume responsibility, while leaving in place a strong counter intelligence and special forces effort proportionate to the threat.”

Former Minnesota governor Tim Pawlenty, in a Fox News interview, called Obama’s speech “deeply concerning” and criticized him for setting a timetable.

“When America goes to war, America needs to win. We need to close out the war successfully, and what that means now is not nation-building,” Pawlenty said. “What it means is to follow General Petraeus’s advice and to get those security forces built up where they can pick up the slack as we draw down.”

Pawlenty and other party leaders have warned against isolationism, yet some Republicans, including Rep. Ron Paul of Texas, a tea party favorite and long-shot presidential candidate, are focusing on cost in calling for scaled-back engagement.

Former Massachusetts governor Mitt Romney said the cost of the conflict, roughly a half-trillion dollars, should not be a factor in deciding the course of the war.

“We all want our troops to come home as soon as possible, but we shouldn’t adhere to an arbitrary timetable on the withdrawal of our troops from Afghanistan,” Romney said in a statement. “This decision should not be based on politics or economics.”

Newt Gingrich called for a comprehensive review of Afghanistan, Pakistan and Libya.

"Given the reality of the larger war that President Obama refuses to name, it's not responsible to make a decision on Afghanistan in isolation just in order to meet a domestic political agenda,” Gingrich said in a statement.