Under the original Pentagon war plan, a powerful force of Army tanks and tens of thousands of troops now would be bearing down on Baghdad from northern Iraq as other heavily armored troops converged on the capital from the south.

Neither is happening. In the south, Army troops and Marines are bogged down by supply problems and unexpected Iraqi resistance. In the north, 1,000 lightly armed U.S. paratroopers only arrived Wednesday night, not enough to seriously challenge the Iraqi government. The reason is that Turkey, a close NATO ally that shares a 218-mile border with Iraq, earlier this month refused a Bush administration request to permit the armored troop deployment from its soil.

One week into the war, the administration's inability to win Turkey's approval has emerged as an important turning point in the U.S. confrontation with Iraq that senior U.S. officials now acknowledge may ultimately prolong the length of the conflict. It is a story of clumsy diplomacy and mutual misunderstanding, U.S. and Turkish officials said. It also illustrates how the administration undercut its own efforts to broaden international support for war by allowing its war plan to dictate the pace of its diplomacy, diplomats and other experts in U.S.-Turkish relations said.

Turkey's rejection was especially surprising to administration officials because Turkey has loyally backed U.S. military actions since the Korean War a half-century ago. In retrospect, U.S. officials say, they made unrealistic demands on the new government of Turkey, which was installed only in November, insisting on a vote on whether it would accept as many as 90,000 U.S. troops even as President Bush was still publicly claiming he had made no decision to attack Iraq. U.S. officials repeatedly set deadlines for action, but then took no action when the deadlines passed, costing the administration credibility and inflating Turkey's sense of importance.

Some senior officials in Turkey, where 94 percent of the population opposed the war, even began to believe they could halt a military conflict through inaction on the U.S. request. The Turkish prime minister at the time, Abdullah Gul, appeared racked with doubts about a war, and Turkish officials suggest he secretly opposed the American troop request.

The deadlines were never real, U.S. officials admit now, but merely a feint to keep pressure on Turkey. The Pentagon augmented the pressure by keeping three dozen ships packed with tanks and heavy equipment for the Army's 4th Infantry Division bobbing off the Turkish coast in the eastern Mediterranean awaiting permission to offload.

When the Turkish government finally agreed to schedule a vote on the U.S. request on March 1, parliament voted it down.

The State Department and Vice President Cheney's office both pushed to send the ships to Kuwait to shore up the Marines and Army forces assembling there for a southern invasion. Bush, in fact, had warned Turkish officials that the United States did not need a northern front for a successful war, according to a senior administration official.

But the military, in particular Army Gen. Tommy R. Franks, the head of U.S. Central Command and one of the chief architects of the war plan, clung to the idea that Turkey ultimately would accept the troops, officials said. The Pentagon insisted that administration diplomats press the government in Ankara to reverse the vote.

The ships started moving through the Red Sea to Kuwait only after the war started last week, and the 4th Infantry Division will not be ready to move into Iraq until at least mid-April.

"The Turks came to think we would pay anything for their cooperation," a senior U.S. official said. "The Turks got to believe they were indispensable, and it colored their capacity to decide when they had negotiated enough."

Yasir Yakis, the former Turkish foreign minister who played a key role in the talks with the United States, was quoted saying as much last week in the newspaper Vatan. "We thought the United States needed the northern front. We made bargaining plans based on this. We did not consider the possibility that they would apply Plan B," he said, using the phrase for an invasion of Iraq without Turkish cooperation.

Turkey's rejection not only forced a rewrite of the war plan, but it undercut the administration's broader diplomatic efforts to win international support for an invasion. Diplomats said the image of Turkey resisting U.S. pressure emboldened smaller countries on the U.N. Security Council to reject a proposed U.S.-British resolution authorizing military action. The failure of that resolution in turn made it impossible for the United States to recruit such close allies as Canada and Mexico to join the fight against Iraq, since they had tied their support to a new resolution.

Moreover, the impasse seriously damaged U.S.-Turkish relations, administration officials now acknowledge. Turkey was the last NATO ally to grant permission for U.S. warplanes to enter its airspace for the war, and a U.S. special envoy has been in and out of Ankara this week to prevent Turkey from sending its own troops into northern Iraq. Once portrayed as an indispensable ally and the U.S. model for a Muslim democracy, Turkey now finds itself scorned by Washington and in a position to be blamed if the war goes poorly.

Both sides clearly failed to see that the other had changed in important ways since they cooperated during the Persian Gulf War in 1991, analysts said. More broadly, two countries that forged a Cold War alliance against a common Soviet threat found their interests diverging sharply in the case of a war in Iraq.

"The relationship with the United States, which had at one time seemed so special and fundamental, has been badly frayed," said Morton Abramowitz, who was U.S. ambassador to Turkey during the first Gulf War. "There is unhappiness and frustration in the U.S. government."

'Support Is Assured'

In early December, Deputy Defense Secretary Paul D. Wolfowitz flew into Ankara for talks with Turkish leaders. He emerged exuberant. "Turkish support is assured" for a war with Iraq, Wolfowitz told reporters. "Turkey has been with us always in the past, and they will be with us now."

Despite Wolfowitz's enthusiasm, however, the undercurrents of a debacle were already in motion. Polls showed more than 90 percent of the Turkish public opposed a war. Some U.S. officials, meanwhile, were uncomfortable with the size of the request contemplated by the Pentagon -- originally 90,000 troops, later dropped to 62,000 -- because they were worried that it was too much for Turkey, a Muslim country being asked to support a war against a Muslim neighbor.

But most U.S. officials took comfort in the judgment that Turkey's political establishment, especially the influential military, could be relied on to support the United States. Historically, the military and the political elite have been at the forefront of Turkey's westernization and modernization. But the Bush administration failed to recognize the tremendous changes that have swept Turkish society, including the military, over the past decade, as well as the country's deep frustration with how it fared after the 1991 Gulf War.

Turgut Ozal, the popular Turkish president, strongly backed the United States in the 1991 war, opening Turkish airspace and air bases and even pushing to send Turkish troops to help expel Iraq from Kuwait. Afterward, however, the United States failed to come through with all its promises of economic aid in return for Turkey's support. Because Iraq was Turkey's largest trading partner, the Turkish economy suffered, beginning a slide that culminated in 2000 with a financial crisis in which the currency collapsed and unemployment skyrocketed.

Equally important, Turks blamed the Gulf War for emboldening Kurdish separatists, who began using northern Iraq as a base of operations to attack Turkey from their strongholds in the country's southeast. More than 30,000 people died in the ensuing conflict, perhaps half of them Turkish soldiers, before the 1999 cease-fire that followed the capture of Kurdish separatist leader Abdullah Ocalan by Turkish special forces in Kenya.

Though the United States helped capture Ocalan and condemned his Kurdistan Workers' Party as a terrorist group, it also criticized Turkey's human rights record during the war and its refusal to grant Kurds full cultural rights. These criticisms, and U.S. assistance to the Iraqi Kurds in northern Iraq, fueled suspicions in the Turkish military about U.S. intentions.

Mumtaz Soysal, a former Turkish foreign minister, said the military resisted the current Bush administration's plan to attack Iraq because it was worried the United States might allow Iraqi Kurds to establish an independent state, which could encourage more separatist fighting in Turkey. "This was our Vietnam War," he said. "The military took all risks, and at a high cost in lives, they finally succeeded. It was an expensive victory, and they don't want that victory to be wasted."

At the same time, Turkey's military and political elite is not as powerful as it once was. In November's elections, voters threw out all of the previous governing parties and allowed the fledgling, anti-establishment Justice and Development Party to form a government on its own. The military, which has long viewed itself as the guardian of a secular Turkish state, viewed the result with alarm because the party has roots in political Islam. The military therefore had its own reasons for wanting the country's new leaders to fail in their first major test with Washington.

The new government, beset with crises involving the country's efforts to gain entry into the European Union and U.N. attempts to negotiate a peace settlement in Cyprus, dragged its feet on dealing with the troop request. In early February, Cheney called Gul and urged him to call a vote in parliament within days, just before the Muslim holiday of Bayram, Turkish officials said. Gul said no -- he said he would try to arrange it by Feb. 18 -- but word of the phone call spread and contributed to a belief in Ankara that the United States was oblivious to the political predicament faced by the Justice and Development Party.

'Do This Ourselves'

The week before the parliamentary vote that U.S. officials expected on Feb. 18, a delegation led by Yakis arrived in Washington to discuss Turkey's financial package for agreeing to the troop request. The administration had offered $4 billion -- $2 billion in grants and $2 billion in military credits. But a day of negotiations went nowhere.

Administration officials even arranged a meeting between the Turks and House Speaker J. Dennis Hastert (R-Ill.), who assured them Congress would honor the president's budget request for Turkey. Yakis preferred a written commitment, but the Turkish ambassador, Faruk Logoglu, told him Hastert's word was the best they could get under the U.S. system.

That night, at 9, Yakis called Secretary of State Colin L. Powell at home and insisted he had to see him. Powell was due to fly early the next morning to New York to haggle with France and other U.N. Security Council members over whether to continue weapons inspections in Iraq. But he agreed that Yakis and the Turkish economics minister could come to his spacious McLean home at 10:30. When they arrived, Powell, still dressed in jacket and tie, ushered them into his dining room, according to an official who was present. He didn't offer them food or a drink.

Yakis told Powell the $4 billion offer wasn't enough. He had consulted with Ankara and his government had decided to ask for $92 billion over five years, the official said. Failing that, Ankara wanted $22 billion in the first year.

Powell noted that the entire foreign aid budget for the United States was $18.5 billion. As the clock neared midnight, Powell told them he would ask Bush to raise the U.S. offer to $6 billion, with $1 billion that could be used immediately for a loan of $8 billion to $10 billion.

During the negotiations, Bush had made only a handful of calls on the troop request. U.S. officials more or less expected the Turkish delegation's meeting with the president in the Oval Office the following day would seal the deal. Bush told Yakis he would agree to Powell's $6 billion offer, but that was the maximum. "You are great negotiators," Bush said, according to U.S. and Turkish officials. "You got me to my top line. But it really is my top line."

Bush added that the decision was now up to Turkey. "We'd like you to be with us," he said. "But if you decide not to be with us, that's okay. We can do this ourselves."

'Time Ran Out'

The Feb. 18 date came and went. No vote took place. U.S. officials announced the equipment-laden ships would begin moving from the Mediterranean to Kuwait in 48 hours. But they didn't move, and in fact, more started to gather off the coast.

In Turkey, senior party officials said, a significant faction within the government believed Turkey could prevent a war by dragging out the negotiations and voting no if necessary. This view was reinforced by resistance to U.S. plans at the United Nations, and also by a meeting on Feb. 18 between Gul and French President Jacques Chirac during which Chirac praised the Turkish position, the officials said. Chirac was spearheading efforts at the United Nations to continue inspections and avoid a war.

"We tried very hard to prevent the war," acknowledged one senior Turkish official, speaking on condition of anonymity. "Many believed it was possible. They didn't understand the Bush administration wouldn't listen."

Gul was strongly influenced by this faction, officials said. He visited Syria, Jordan, Saudi Arabia and Iran in a regional peace effort, and hosted a conference of foreign ministers in Istanbul. He also dispatched a minister to Baghdad for talks with Iraqi officials, and sent a plane to bring the Iraqi vice president to Ankara.

"Up to some point, he believed in the notion that Turkey could do something to stop the war," said Fehmi Koru, a popular antiwar columnist and a former classmate of Gul's. "But when time ran out, and the U.S. pressure increased, he realized it was impossible."

"As one after another after another deadline passed, they couldn't understand what we were all about, and figured they could just keep this going on forever," acknowledged a senior administration official.

By the time the vote was finally scheduled on March 1, party officials said Gul's qualms about the war were so obvious, he was unable to persuade parliament to approve the U.S. deployment. Speaking to parliament before the vote, lawmakers said, Gul failed to make a convincing case. "We could tell his heart wasn't in it," said one lawmaker.

M. Akif Beki, a senior journalist in Ankara, said the Bush administration failed to see that its request came at a juncture in Turkish history when the military and political establishment was turning away from the West while the country's Muslim traditionalists were embracing Western democratic values.

After all the months of delays and negotiations, U.S. officials themselves were split on how the vote would turn. "Some were absolutely convinced it would pass. It was Turkey and we are the United States," said a senior administration official. "The people who understood how arrogant we were, they understood it was a dicey vote."

The motion failed by three votes.

On Capitol Hill yesterday, Wolfowitz acknowledged that the parliamentary rejection made a "big difference" in the war. "There is no question," he said, "that if we had a U.S. armored force in northern Iraq right now, the end would be closer."

Pan reported from Ankara.

Turks celebrate this week as a U.S. Army unit leaves for the port of Iskerendun, en route to Kuwait, as a result of the abandonment of U.S. plans to launch an offensive into Iraq from Turkey.