Hamas, a violent Islamist movement whose charter calls for the destruction of Israel, had won Palestinian parliamentary elections — elections that were deemed free and fair and a cornerstone to President Bush’s initiative to bring more democracy to the Muslim world.

For the next 17 months, White House and State Department officials would undertake an all-out campaign to reverse those results and oust Hamas from power.

Instead of undermining Hamas, though, the strategy helped to exacerbate dangerous political fissures in Palestinian politics that have delivered another setback to the president’s vision of a stable, pro-Western Middle East.

The administration’s drive to change the political facts on the ground foundered on opposition in Congress, the differing goals of Middle East allies such as Saudi Arabia, and an inability to provide Palestinian Authority President Mahmoud Abbas with the full backing he needed to confront Hamas.

Three weeks ago, Hamas leaders outmaneuvered everyone else and seized the Gaza Strip in a swift military campaign that vanquished secular Fatah forces loyal to Abbas. Abbas, with U.S. encouragement, responded by dissolving the Hamas-led government and declaring emergency rule. Now, with Palestinians divided into two mini-states in Gaza and the West Bank, mediating a peace deal with Israel will be harder than ever.

The strategy toward Hamas was overseen by Secretary of State Condoleezza Rice and carried out largely by Elliott Abrams, a leading neoconservative in the White House, and Assistant Secretary of State David Welch.

At its heart was a plan to organize military support for Abbas for what opponents of the strategy feared could have become a Palestinian civil war, according to officials in Washington and the Middle East, and documents.

As recently as March, Jordanian officials developed a $1.2 billion proposal to train, arm and pay Abbas’ security forces so they could control the streets after he dissolved the government and called new elections. McClatchy Newspapers obtained a copy of the plan. While two sources close to Abbas said U.S. officials were involved in developing and presenting the plan, a State Department official described it as a Jordanian initiative.

Ultimately, congressional concerns in Washington and Israeli objections kept any significant military aid from being delivered, even as Israeli intelligence and the CIA warned that Hamas was becoming stronger.

Long term, the U.S. effort to oust Hamas has further deepened doubts about the administration’s understanding of the region.

“America is so far away, they are completely misinformed about what is happening,” said Munib Masri, a Palestinian businessman allied with Abbas. “The more they do against Hamas, the more power they [Hamas] get from the people.”

Well before the January 2006 elections, the White House and Rice had ample warning about the risks of allowing Hamas to participate, according to two senior U.S. officials.

But Abbas argued that elections wouldn’t be credible without Hamas, and Washington went along, said one of the senior U.S. officials, who spoke on condition of anonymity because of White House-imposed ground rules.

Once Hamas was elected, the White House gave almost no thought to accepting the results and trying to co-opt the hard-line Islamist group, which the U.S. government deems a terrorist organization, current and former U.S. officials said.

Instead, Rice orchestrated an international financial boycott of the new Palestinian government, an action that failed to weaken Hamas or force it to moderate its views.

Simultaneously, throughout the spring and summer of 2006, the United States pressed Abbas to confront Hamas and dismiss the government to end the paralysis in the Palestinian Authority.

Abbas “just refused,” said Edward Abington, a former U.S. diplomat who advises the Palestinian president. “He was afraid there would be armed rebellion.”

As the financial pressure on the Hamas-led government failed to undermine it, the Bush administration increased emphasis on training and arming Abbas’ security forces. But resistance from Congress and Israel prevented this third element in the U.S. plan from getting off the ground.

In February, Abbas joined forces with Hamas to form a national unity government. Israel and the United States felt betrayed by the deal. Hamas attacked in mid-June, sweeping away Fatah’s forces in Gaza in a matter of days.

As Rice and Israel again move to bolster Abbas with millions of dollars in previously blocked funds, some current and former U.S. officials say the Bush administration has underestimated Hamas and failed to recognize how dysfunctional its Fatah ally had become.

Said Aaron David Miller, who advised six secretaries of state on Arab-Israeli negotiations: “I don’t know if we grasp it even now.”

Nissenbaum reported from Jerusalem and Gaza.