No one would have guessed 25 years ago that liberal Democrats in Congress would be wholeheartedly endorsing a US-led bombing campaign, or that Republican veterans would be reluctant, clamoring for an "end game."
But as American pilots continue to rain missiles on targets in Yugoslavia, the reaction on Capitol Hill underscores a fundamental shift in views on military intervention in the post-cold-war era.
Hesitance within the GOP exposes an isolationist strain in the party obscured by decades of anticommunist hawkishness. Meanwhile, even dovish Democrats are increasingly embracing the use of force to advance humanitarian aims, say experts.
Behind the split are contemporary political calculations and an enduring debate over how much might the US should expend on behalf of people outside its borders. "Democrats are more willing to intervene to support human rights and oppose aggression," says former Rep. Lee Hamilton, a Democrat who chaired the House Foreign Affairs Committee and now heads the Woodrow Wilson International Center for Scholars.
Of course, as is often the case in Congress, the ideological lines remain somewhat blurry. Most important, significant differences over the post-cold-war rationale for exerting US military force exist within the Republican camp, throwing into question the GOP's effort to craft a coherent foreign-policy and defense platform as a pillar of the 2000 election campaign, analysts say.
"There is a growing divide in the Republican Party ... because the end of the cold war has made it less clear what American interests are overseas," says Thomas Moore, director of international studies at the conservative Heritage Foundation in Washington. "So it's easy to fall into a state of confusion when a decision arises over our use of military force."
Moreover, ideology is not the only driving force behind the positions being staked out on Capitol Hill. Political loyalties and a heightened tendency toward partisanship are other major factors.
"This is inextricably tied up with who is in the White House," says Congress scholar David Rohde at Michigan State University in East Lansing, Mich.
Many Democrats, for example, feel politically compelled to rally around President Clinton's decision to order airstrikes to force Yugoslav President Slobodan Milosevic to halt his offensive against ethnic separatists in Kosovo. "The Democrats simply accept the president's analysis more than the Republicans do," says Mr. Hamilton.
For the same reason, Republicans - generally more leery of Mr. Clinton following the scandal and impeachment - are far less inclined to back the president's use of military force.
"Many Republicans are reluctant to throw their support behind this president in a complex military action," says Robert Kagan, a former Reagan administration official now at the Carnegie Endowment for International Peace. "They just don't trust him."
BOLSTERING this dynamic is a growing partisan chasm within Congress - one some say is unprecedented this century - reflected by a surge in party-line votes in recent years.
Congress, moreover, may be more outspoken today in making its divergent views on military action known to the public. House Speaker Dennis Hastert recently underscored lawmakers' unwillingness to leave decisions on US armed intervention to the White House.
"Congress must have a meaningful role in this decision, no matter how difficult our choice," said Speaker Hastert (R) of Illinois. He brushed aside criticism that his decision to allow the House earlier this month to debate the deployment in Kosovo would undermine the peace process.
Yet underlying the usual political tug-of-war between Congress and the White House, experts detect a broad ideological switch in Republican and Democratic views on military intervention spurred by a new US role in the world.
Republicans, no longer united by the cold-war goal of defeating communism, are grappling with new ways to define America's national interest - always the GOP's foremost justification for military action abroad. In the debate over Kosovo, many Republicans argue they could not identify a compelling national interest that would justify the cost to the US in terms of military resources and potential loss of life.
"The situation in Kosovo, as tragic as it is, does not directly threaten US security," said House Armed Services Committee chairman Floyd Spence (R) of South Carolina. Echoing many other Republicans, Mr. Spence decried "involvement in an open-ended military operation" in Yugoslavia.
"Could I look one of my neighbors in the eye and tell them, with conviction, that their loved one died in Kosovo in defense of America's vital interests? The answer is no," said Rep. Tillie Fowler (R) of Florida, whose amendment to block the deployment of US ground troops failed in the House.
Democrats, in contrast, framed their support for the military strike less in terms of narrow US national interests. Instead, describing themselves as "internationalists," they said the action was necessitated by risks to global security and the collective humanitarian goal of stopping ethnic cleansing.
"With genocide in the heart of Europe, it is appropriate for NATO [the North Atlantic Treaty Organization] to get involved," says Rep. Eliot Engel (D) of New York. "The United States is the only one that can lead the charge in stopping it" and preventing a larger Balkan war, he stresses.