The Post And Courier, Grace Beahm, Associated Press
Republican presidential candidate former Massachusetts Gov. Mitt Romney greets Bud Watts, left, as he arrives to speak to supporters aboard the USS Yorktown, Thursday, Oct. 6, 2011, at Patriots Point in Charleston, S.C.

CHARLESTON, S.C. — Republican presidential candidate Mitt Romney said Friday government leaders reach for a century of American dominance, outlining proposals to strengthen the military while rejecting multilateral institutions like the United Nations when necessary.

On the 10th anniversary of the war in Afghanistan, the former Massachusetts governor also promised a full review with military commanders but he offered no clear direction for the conflict that is growing increasingly unpopular, even among conservatives. And he condemned the isolationist policies supported by some tea party activists.

"This is America's moment. We should embrace the challenge, not shrink from it, not crawl into an isolationist shell, not wave the white flag of surrender, nor give in to those who assert America's moment has passed. That is utter nonsense," Romney told cadets and others at the The Citadel, South Carolina's military college.

Romney's first foreign policy speech as a candidate amounted to a show of force of sorts as he tries to position himself as the clear GOP frontrunner in the White House race. Some Republicans remain reluctant to support him but Romney has resumed his place atop national polling following Texas Gov. Rick Perry's recent stumbles and New Jersey Gov. Chris Christie's decision not to run.

The hawkish policies Romney outlined Friday may draw criticism from the libertarian wing of his party but are designed to confront what may be the former businessman's most glaring weakness. While he served as a Mormon missionary in France more than four decades ago, he has only limited foreign policy experience. As he says in nearly every campaign stop, he has spent most of his life in the business world.

Aides insist this is an asset that allows for a thoughtful, business-like approach in shaping a proactive and aggressive foreign policy. To that end, he took a forceful tone in his remarks before 400 people gathered at The Citadel's Mark Clark Hall, a three-story building named for the U.S. general who liberated Rome in World War II.

"This century must be an American century. In an American century, America has the strongest economy and the strongest military in the world," Romney said. "God did not create this country to be a nation of followers. America is not destined to be one of several equally balanced global powers. America must lead the world, or someone else will."

He offered few specifics on Afghanistan, but vowed to conduct a full review in his first 100 days in office to determine "the presence necessary to secure our gains and successfully complete our mission." That's among seven other priorities for the first 100 days that include rebuilding the Navy fleet, ordering aircraft carriers into the eastern Mediterranean and Persian Gulf to help pressure Iran, and deploying of a national ballistic-missile defense system.

The hardline policies, which are in some ways a return to those of the Bush administration, include specifics on various fronts aside from Afghanistan.

When pressed for details during a morning briefing, a Romney foreign policy advisor declined to outline a Romney plan for Afghanistan and noted that the governor recognizes the difficulty of what America faces in it.

Romney also called for working with the United Nations when appropriate.

"But know this," he says. "While America should work with other nations, we always reserve the right to act alone to protect our vital national interests."

A day earlier, Romney called for 100,000 new troops, increased military spending and a larger Navy.

"You would think that the president and the people in Washington would recognize the importance of the United States military and the need not to shrink our military budget but strengthen it," Romney told veterans Thursday on the hangar deck of the World War II-era aircraft carrier USS Yorktown.

The exact cost of Romney's plans is unclear, although it may be high.

For example, Romney is calling for the Navy to increase the number of ships constructed each year from nine to 15. He argues that savings in other areas would partially offset the investment.

Romney acknowledged waste in defense spending and "my life in the private sector taught me to go after waste and economize, and there is an opportunity to do that." But he said he wouldn't, as European nations have done, reduce defense to bolster social programs.

The Citadel speech comes three days before his rival Jon Huntsman, the former ambassador to China, delivers a foreign policy address of his own. The location of the speech, in the early voting state of South Carolina, is of course no coincidence.

Peoples reported from New Hampshire.