Republican White House hopeful Jon Huntsman called Monday for the United States to forge trade deals with Taiwan and Japan and warned that, if elected, he might use force to keep Iran from developing nuclear weapons.

"I cannot live with a nuclear-armed Iran. If you want an example of when I would consider the use of American force, it would be that," the former US envoy to China said in a campaign speech laying out his foreign policy vision.

He vowed to take a tougher line on Pakistan, charging it has a "fractured military that sponsors terrorism," while seeking closer ties to India -- including by backing its bid to become a permanent UN Security Council member.

Huntsman also pushed for the United States to "end nation-building" as a tool of statecraft and called for a swift withdrawal from Afghanistan, which he said was no longer the epicenter of Islamist extremist threats to US targets.

"We must right-size our current foreign entanglements," the former Utah governor said at a university in the key early-primary state of New Hampshire.

Huntsman declared that the United States "should pursue trade agreements with Japan and Taiwan" -- a step likely to anger China, which considers Taiwan a breakaway province awaiting reunification.

A top US diplomat in July ruled out a US-Taiwan free trade agreement for now amid a dispute over beef imports, but supporters of such a measure say it could pave the way for the island's neighbors to seek closer economic ties.

Negotiations between the United States and Taiwan on a Trade and Investment Framework Agreement, often a precursor to a full-fledged FTA, have been dormant since 2007.

Taiwan is a member economy of the Asia-Pacific Economic Cooperation forum and joined the World Trade Organization -- as "Chinese Taipei" -- on January 1, 2002.

A Huntsman aide said his goal was "not formal diplomatic relations" with Taiwan but "to develop more robust economic ties."

Huntsman, who said two weeks ago that he would sign legislation that aims to punish China for its alleged currency manipulation, warned that the measure "in practice would be bad, because it would result in a trade war."

At the same time, he said he would use the bill, which was expected to clear the US Senate on Tuesday, as "leverage" to get China to let its yuan appreciate "just a little bit faster and a little more aggressively."

Huntsman also assaulted his former boss's handling of world affairs, charging that President Barack Obama's "policies have weakened America, and thus diminished Americas presence on the global stage."

"We must correct our course," said the former diplomat, who is seen as a long shot for the party's nomination to take on Obama in the November 2012 elections.

Huntsman said the US military must become more agile -- not bigger -- and said that when it comes to Afghanistan "it is time to bring our brave troops home" while leaving an unspecified number of counterterrorism, intelligence, and special forces assets there.

"Afghanistan was once the center of the terrorist threat to America. That is no longer the case," he said.

"We must be prepared to respond to threats -- from Al-Qaeda and other terrorist cells -- that emanate from a much more diverse geography, including Yemen, the Horn of Africa, Pakistan and the Asia-Pacific," he said.