CEDAR RAPIDS, Iowa – Mississippi Gov. Haley Barbour, openly courting first-in-the-nation Iowa caucus voters, doubled down on his misgivings about U.S. military action in Afghanistan Friday, suggesting that “mission creep” had given U.S. forces an impossible task of nation-building in one of the world’s poorest, most corrupt countries.

Speaking to Linn County Republicans, Mr. Barbour said: “We need to step back in Afghanistan, and we need to decide whether the resources we’re putting into Afghanistan, 110,000 soldiers and about $2 billion a week, are essential for our mission.”

That mission is “to stamp out, to obliterate, to kill if necessary the terrorists who were using Afghanistan” before the Sept. 11 attacks, he said. But the U.S. government’s estimate is that only about 100 Al Qaeda members are still in the country.

“Mission creep” has broadened the U.S. mission into making Afghanistan “a country like India, or Italy or Ireland.” That isn’t going to happen, said Mr. Barbour, who is openly taking steps toward a likely campaign for president.