It's become something of a mantra, a campaign's shorthand for how John Kerry's foreign policy would differ from President Bush's: multilateral if we can, unilateral if we must.
"That's a fundamental difference from the current administration's approach to the world, which is 'probably alone, with others if we must,' " says Rand Beers, national-security coordinator for the Kerry campaign.
Clearly Mr. Bush's security policy of preemptive action has become a lightning rod for the presidential campaign. The Iraq war derives from that doctrine - with the president continuing to tell the American people that he will act before America's enemies have a chance to.
At the same time, some experts question whether "multilateralism" constitutes a foreign policy - and whether it adequately responds in any case to the post-Sept. 11 world. Others say the differences that Senator Kerry offers are basically of tone, and that the war on terrorism - like the cold war before it - allows little room for widely differing policies.
Mr. Beers, who left the Bush White House over his strong disagreement with the Iraq war, counters that "multilateralism" is key to how a Kerry foreign policy would be different. He proceeds from the premise that "stateless organizations" like Al Qaeda are at least as threatening as "rogue states," and he says the US can best battle them by coupling strong American leadership with strong alliances.
Taking as an example the problem of terror groups teaming up with weak or sympathetic states, Beers says it's "necessary to find procedures to take these opportunities away from terrorists, rather than believing the threat of force alone will convince" problematic countries to cut the terrorist ties.
To some observers, a Kerry White House would offer a return to a more traditional alliance-based foreign policy broadly followed by administrations since World War II. "Even if you look at any Republican president from Eisenhower through [George H.W.] Bush 41, the basis is on safeguarding US interests by having the world behind what we do," says Lawrence Korb, a Pentagon official during the Reagan administration who is now with the Democratic-leaning Center for American Progress in Washington.
But others counter that such an argument fails to acknowledge how the world has changed - and doesn't outline what Kerry's foreign policy would be. "We're not in a George Bush I world," says Danielle Pletka, a foreign-policy expert at the conservative American Enterprise Institute in Washington. Calling alliances a "means to an end," she says Americans want to know where Kerry thinks he would lead, "especially when we are at war."
Others say Kerry's emphasis on alliances fails to take into account how America's relations with Europe - traditionally its major allies - have changed with or without George W. Bush.
"Kerry's argument would be fine if there was agreement among Western powers about the threat and how to deal with it, but there isn't - and the differences don't derive from the way Bush talks," says Stephen Krasner, a former Bush National Security Council official who is now with the Stanford Institute for International Studies in California.
"There are differences in attitude, capabilities, and power among the allies that are real and growing," he says. "They aren't going to be overcome by changing who's the president."
Those who disagree say the world craves American leadership - but not being told "my way or nothing," says Joseph Wilson, a Kerry supporter and former ambassador who was embroiled in controversy over his investigation into Saddam Hussein's nuclear pursuits in Africa.
The Kerry camp says their candidate believes a certain amount of compromise and extra time to bring allies onto a plan is worth it in the long run.
"It may take some time to make them feel confident to be part of the solution, but over time it serves our interests and reduces our costs and losses," Ambassador Wilson says.
For Ms. Pletka of the American Enterprise Institute, a bigger worry lies in Kerry's congressional work on foreign policy. She says that as a Republican staffer on the Senate Foreign Relations Committee for 10 years, she saw "no Kerry hallmark - he left no trail."
Kerry aides say critics who complain their candidate has no foreign policy haven't been listening - and they outline four key areas where he would focus attention on national security: building alliances; strengthening a military that many see as overextended; making more use of America's economic power to address problems; and revamping energy policy to reduce dependence on Middle East oil.
Those are the kinds of campaign points that voters will be weighing to see how much - or if - Kerry is different from Bush. "It's an absolutely critical center-stage issue," says Beers. "This is a foreign-policy election."