President Clinton is on the verge of clinching a major foreign-policy victory, one that paves the way for a historic realignment of Europe's geopolitical map.
The Republican-run Senate is expected to approve by a comfortable margin the admission of Hungary, Poland and the Czech Republic into the North Atlantic Treaty Organization in the first round of its expansion into formerly communist Eastern Europe.
The vote - slated for next week - will likely ensure ratification by all the16-member alliance's legislatures. The admission of new members will take place next year.
With many of his other diplomatic initiatives facing uncertainty, the Senate vote will represent a personal achievement for Clinton as he strives to shape a legacy as an international statesman.
NATO expansion is among his most far-reaching foreign-policy initiatives, involving issues ranging from relations with Russia and post-cold-war budgets to putting American lives at risk in new areas of the globe. Since adopting the initiative in 1994, he has invested enormous time, energy, and prestige in building support at home and abroad.
Yet the debate that precedes the Senate tally promises to be fierce, reflecting persisting divisions among officials, academics, and others over extending NATO's nuclear and conventional security shields into what was enemy territory for more than four decades.
Says an administration official: "We are confident we will have the two-thirds [vote of the Senate] we need to ratify. Nevertheless, I think the debate will be vigorous."
Many lawmakers, including some supporters, harbor deep misgivings about the expense of enlarging the United States-led alliance. Some say the White House has deliberately low-balled the cost estimates to ensure Senate approval, an allegation administration officials deny.
There are also grave concerns over the impact of NATO expansion on already difficult US-Russia relations. Russia remains deeply upset by the pact's move closer to its borders despite the creation of a special council in which it can voice its views on NATO policies. The Russian parliament has cited NATO expansion in refusing to ratify a 1993 nuclear arms reduction accord with the US.
Seventeen senators want the vote delayed, arguing that the Senate needs more time to deliberate the consequences of expansion. Some also want a moratorium on bringing more countries into NATO until the impacts of the admissions of the first new members can be fully assessed.
"I am concerned that we not do anything to undermine the effectiveness of this great alliance," asserts Sen. John Warner (R) of Virginia. He plans to propose an amendment requiring a "strategic pause" of up to five years in new NATO admissions.
But opponents are unlikely to succeed in delaying the vote or altering the legislation approved by a 16-2 margin by the Senate Foreign Relations Committee on March 3.
With congressional elections in November, few lawmakers are likely to oppose an initiative sought by millions of voters of Eastern European extraction.
Beyond domestic politics, lawmakers see NATO expansion as a way of correcting an historic wrong in which the West allowed the former Soviet Union to subjugate Eastern Europe after World War II.
They also concur in the Clinton administration's view that NATO enlargement will enhance Europe's security by bolstering the new Eastern European democracies and ending age-old feuds that have ignited two major wars this century, forcing US intervention.
"A large NATO will make American safer by expanding the area of Europe where wars do not happen," Secretary of State Madeleine Albright asserted before the Senate Foreign Relations Committee on Feb. 24.
"The bottom line is that the Senate will ratify," says Prof. Sean Kay of Dartmouth College, in Hanover, N.H., the author of a forthcoming book on NATO expansion. "But somebody has to implement this and there are still serious questions that have to be dealt with so that the policy will succeed."
Perhaps the most pressing questions concerns the costs. The US, its allies and the new members will have to upgrade communications, air defenses, and infrastructure so that NATO forces can operate on the new members' territories.
The new members will also have to modernize their forces, the bulk of whose equipment is outmoded Soviet-era hardware.
In February 1997, the administration put the costs of expansion at up to $35 billion over 13 years; the US share would be up to $2 billion. Other studies have put the overall figure as high as $125 billion. But a new Pentagon study has dramatically lowered the total amount to $1.5 billion over 10 years, with the US paying $400 million.
US officials defend the new estimates by saying the other studies used the wrong methodologies and that Czech, Hungarian, and Polish military facilities are in much better condition than originally thought.
But critics say the Pentagon was forced to lower estimates after its European partners refused to pay their shares of the costs. And they assert that the new figure does not include funds the European allies, which are cutting defense spending, will have to spend to give their forces the abilities to deploy quickly to the pact's new borders.
"The issues raised about cost I think are not unfounded," concedes Sen. Christopher Dodd (D) of Connecticut, even though he voted with the majority of the Senate Foreign Relations Committee for the legislation.
Finally there are grave doubts among some experts that the Czech Republic and Hungary will be able to afford their modernization programs, leaving US taxpayers to pick up the slack.