And when he has given details, these experts say Ronmney's hard-line approaches could end up putting the United States in greater international conflicts.
"This is a governor and a businessman running essentially on economic issues," said Anthony Cordesman, a former national security aid to McCain who is now at the Center for Strategic and International Studies. "He doesn't really have a history of being briefed on national security and defense. It's now very clear this is not his natural area of strength."
On preventing Iran from developing a nuclear bomb, for example, the Romney campaign said he would draw a clear "red line" that, if crossed, would trigger U.S. military action against Iran. Obama also has pledged prevent Iran from building a nuclear weapon, but he has refused demands by Israeli Prime Minister Benjamin Netanyahu to enunciate such a red line.
Romney "has said openly that he would outsource our Middle East policy to Israel," Freeman said. "That's quite remarkable. I don't think anyone in our history has ever run on a platform of outsourcing our foreign policy."
In March, Romney called Russia "our No. 1 geopolitical foe," prompting head-scratching among foreign policy experts, who see the relationship as far more nuanced given our working relationship with the former Cold War enemy.
Russian President Vladimir Putin recently used Romney's stance as ammunition to dig in on Moscow's opposition to a U.S. missile defense system in several European locations. Washington has always maintained that the missiles are a defense against a possible missile attack by Iran, but Russia sees it as a threat to its security.
"I'm grateful to him for formulating his stance so clearly because he has once again proven the correctness of our approach to missile defense problems," Putin said last week, according to the Associated Press.
Romney also has taken a hard-line stand toward China's moves to depress the value of its Yuan currency in an effort to undercut competition to its exports. Last week, during a campaign appearance in Fairfax, Va., he repeated his pledge to declare China a currency manipulator in his first day in office.
Most foreign policy experts say such a move would trigger a trade war with the nation's largest creditor. "It would put us into a confrontational, rather than a conciliatory mode," Freeman said.
Cordesman said such positions reflect the strong neo-conservative cast of his advisers.
"A lot of this, frankly, gives me the impression that he has a very weak foreign policy team, one that isn't politically astute, and which has ideological elements which aren't terribly practical," Cordesman said. "The danger for Romney is that he has allowed himself to be pushed into making statements that are too binding, with too clear a set of deadlines."
Cordesman said Romney still has time to present a more substantial vision of America's place in the world.
"If I were a senior Member of Congress, I would tell Romney you need much better advisers in terms of what you say publicly. And second, I would tell him he needs to broaden his foreign policy team in a hurry," Cordesman said. "This isn't a matter whether you're conservative about foreign policy or whether you take a strong position. It is simply a matter of sophistication and understanding."