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Preparing to present a weary nation with his highly anticipated new war plan, President Bush faced Democrats determined to confront him over sending thousands more Americans to Iraq. Fresh troops are to be in place within three weeks.

For a little over 20 minutes Wednesday night, Bush is to explain why a gradual buildup of about 20,000 additional U.S. troops, along with other steps expected to include pumping $1 billion into Iraq's economy, is the answer for a war that has only gotten deadlier with no end in sight.

After nearly four years of fighting, $400 billion and thousands of American and Iraqi lives lost, the White House calls the president's prime-time address from the White House library just the start of a debate over Iraq's many problems.

"This is not, 'Give one speech, dust your hands off and walk away,'" presidential spokesman Tony Snow said Tuesday. "This is the beginning of an important process for the American people and for the political community to think seriously about."

The address — one of the most pivotal of Bush's presidency — is the centerpiece of an aggressive public relations campaign that also will include detailed briefings for lawmakers and reporters, trips abroad by Cabinet members and a series of appearances by Bush starting with a trip Thursday to Fort Benning, Ga.

Since Friday, Bush has briefed about 100 lawmakers — meetings that were to culminate Wednesday with Congress' Democratic leadership and their Republican counterparts.

Bush on Tuesday also talked by telephone with key foreign allies. He filled in the leaders of Britain, Australia and Denmark, with more calls planned.

Crafting the new policy took the president nearly three months. Relevant agencies conducted reviews, outside experts were called in, and the president consulted several times with Iraqi Prime Minister Nouri al-Maliki and other prominent Iraqi leaders.

In the meantime, the sectarian violence in Iraq continued unabated, and public approval of Bush's handling of the Iraq war hit a record low of 27 percent in December, according to an AP-Ipsos poll.

Democrats, energized by their return to power in Congress in November elections widely viewed as an Iraq referendum, laid plans to challenge Bush's strategy even before he revealed it.

House Speaker Nancy Pelosi, D-Calif., pledged to hold a vote on the troop increase. Many Democrats are likely to oppose an increase, as are some Republicans. Pelosi spokeswoman Jennifer Crider said she said did not know when the vote would occur, or what the legislation would include.

Senate Democrats were planning a vote next week on nonbinding legislation that would urge the president not to send more troops. Senate Majority Leader Harry Reid (news, bio, voting record) said he hoped for a bipartisan measure that would declare, "We don't support this escalation of the war."

If it passes, Reid said, "The president's going to have to take note of that. I think that's the beginning of the end, as far as I'm concerned."

The president will say that the 132,000 troops now in Iraq will be augmented with more sent to both Baghdad, which has been consumed by sectarian violence, and the western Anbar Province, a base of the Sunni insurgency and foreign al-Qaida fighters.

A senior defense official said 20,000 troops will be prepared to deploy, but that the increase will be gradual. The first wave will go before the end of this month, said the official, who requested anonymity because the plans have not yet been announced.

Moving first into Iraq will be the 2nd Brigade, 82nd Airborne Division, which is now in Kuwait and poised to head quickly into the country, the defense official said. The brigade, numbering about 3,500 troops, is based at Fort Bragg, N.C.

Bush is expected to link increases in both U.S. troops and economic aid to moves by the Shiite-led Iraqi government to bridge sectarian divisions. Those include taking steps to curb Shiite militias, enacting a plan to distribute oil revenue to all the country's sects and easing government restrictions on deposed leader Saddam Hussein's Baath Party.

The Baghdad government also will be required to commit more money toward reconstruction and more troops into the fight.

Other components of the president's plan include a bit over $1 billion to shore up Iraq's battered economy and create jobs and a call for friendly Mideast countries — some of which Secretary of State Condoleezza Rice is visiting starting Friday — to increase their aid to Iraq, said a second official, who also requested anonymity.

The president will ignore the recommendation of the bipartisan Iraq Study Group that he include Syria and Iran in an effort to staunch Iraqi bloodshed, the official said.

White House officials say they have new confidence in the promises from al-Maliki — made before, and never kept — that lead them to believe this effort is more likely to succeed than past troop increases.

"The president believes that the Iraqi forces aided by American forces will be able to clean out Baghdad and stabilize Baghdad and leave, as he put it, 'space' for a political reconciliation process to unify the country and stabilize Iraq," Rep. Robert Andrews, D-N.J., said Tuesday after talking with Bush.

While Bush considered his options over the past few months, the number of U.S. military deaths in Iraq passed 3,000, and Saddam was hanged for atrocities committed under his leadership.

Bush also made major changes in his Iraq team. There are, or will be, new faces running the Pentagon in Washington and the war in Baghdad, a new U.S. ambassador to Iraq, a new top American diplomat at the United Nations and a new top intelligence official.