WASHINGTON -- Only weeks after laying out his full foreign policy agenda, Sen. John McCain has begun scaling back a key proposal that had been greeted with alarm by some Republican supporters and wariness by important U.S. allies.

McCain has said that, as president, he would call for creation of a "league of democracies" that would move aggressively to tackle problems the United Nations fails to resolve, such as the Iranian and North Korean nuclear programs, civil strife in Sudan and world health crises.

The idea has been a hit with McCain's neoconservative supporters, who are frustrated with a balky U.N. But a branch of U.S. foreign policy experts known as "realists" have objected that such a group could damage U.S. interests by alienating countries such as China, Saudi Arabia and Russia, which are not democracies but are important U.S. partners.

In Europe, many are concerned that McCain's idea might mask hidden agendas, such as undermining the U.N. or providing a new stamp of international legitimacy to U.S.-led military action.

McCain first proposed a league of democracies last year, describing a formal organization that could use military force as well as economic and diplomatic pressure. It would be organized by the U.S., much like NATO after World War II.

"We should form a league of democracies that can act with great influence and power, both economically and militarily," McCain said on MSNBC on Oct. 16.

In an article in Foreign Affairs magazine in November, McCain called for "linking democratic nations in one common organization" that could provide a common structure for countries whose troops serve on joint missions.

McCain has continued advancing the proposal, citing it again in a speech in Los Angeles in March that marked his first major foreign policy address since becoming the presumptive Republican nominee.

Now, however, McCain says the group would not use military force, and would be an informal organization in which democratic nations come together in different groupings, depending on their concerns.

"It does not envision military action," McCain told reporters in Dallas on April 11. He said it would "not be a formal organization; it would be a coalition of nations that shifts sometimes depending on what their priorities are."

A senior campaign advisor, Steve Schmidt, said in an interview last week that the candidate's concept had not changed. But some outside analysts see an evolution.

James M. Lindsay, director of the Robert S. Strauss Center for International Security and Law at the University of Texas, said McCain's recent description of his idea represented "a sharp departure from what Sen. McCain said previously."

Noting McCain's language in the Foreign Affairs article, Lindsay said that what McCain described to reporters April 11 were "ad hoc coalitions of the willing, which are something quite different, even if they draw on democracies for their main contributors."

Lindsay, who has advocated an organization of democracies of a different sort, served on the National Security Council staff under former President Clinton. He is not affiliated with a presidential campaign.

The implications of such a group, while sounding academic, touch on some of the most hotly controversial foreign policy topics of the last decade, such as when the use of military force is legitimate, and how to deal with international institutions at cross purposes with U.S. administrations.

But the proposal offers insights into McCain's views, which, while usually conservative, can vary according to the issue. McCain is known for his hawkish position on the Iraq war, but he has taken a strong stand against interrogation practices he considers torture, and argues that the U.S. needs to rely more on global alliances.

The idea of a league of democracies would seem to be a political winner for McCain in his effort to attract voters with a wide spectrum of views.

Liberal internationalists as well as neoconservatives have championed versions of the idea as a way to advance good government and solve world problems, unhindered by autocratic governments and international organizations.

In 2000, Clinton's secretary of State, Madeleine K. Albright, helped create a forum called the "community of democracies" that brings countries together in hopes of spreading democratic practices.

Yet to some, the idea is highly provocative.