One thing is clear about John McCain's foreign policy views: Much like his political heroes Ronald Reagan and Theodore Roosevelt, he believes that America's power is a force to make the world better.

How McCain would wield that power as president is less clear, however.

The Arizona senator, now the presumptive Republican presidential nominee, is a leading supporter of President Bush's troop "surge" in Iraq — a stance that some observers credit with reviving his political fortunes as security in Iraq has improved, at least temporarily.

Less well known are McCain's promises, if elected, to expand the Army and the Marine Corps to 900,000 soldiers and Marines from a planned strength of about 750,000; to form a U.S.-led League of Democracies to act when the United Nations can't or won't; and to form a new government unit, patterned after the World War II-era Office of Strategic Services, "to fight terrorist subversion" and "take risks that our bureaucracies today rarely consider taking."

McCain's foreign-policy advisers are a mix of traditional Republican "realists," who favor a pragmatic approach to the world, and "neoconservatives," who lobbied for the Iraq invasion, advocate tougher action to squelch Iran's and North Korea's nuclear weapons ambitions and favor using U.S. power to transform the Muslim world.

McCain has broken with his party on some key issues. He's taken a more lenient stance on immigration, expressed greater concern about global climate change and opposed the Bush White House on the Guantanamo Bay prison and the use of interrogation techniques that could be considered torture.

In Norfolk, Va., on Friday, he talked tough on Iran and said he's best prepared to deal with security threats on his first day in office.

Democratic candidates Sens. Hillary Clinton and Barack Obama "want to set a date for withdrawal in Iraq. I believe that would have catastrophic consequences. They (terrorists) would try to follow us home," McCain said.