The Nation - For Bush, another key moment in the war - In an address tonight, he is expected to support Gen. Petraeus' troop drawdown plan.

WASHINGTON — One speech was famously delivered on an aircraft carrier in front of a "Mission Accomplished" banner. In another, he acknowledged the previous year in Iraq had not turned out well. Frequently, he has stressed the theme that the United States must fight terrorists in Iraq, or "they will not leave us alone."

In more than half a dozen speeches to the nation about Iraq, President Bush has presented his case for the now more than 4-year-old war. His emphasis has shifted as conditions have changed. He has grudgingly recognized mistakes -- and even that some of the intelligence on Iraq turned out to be faulty.

But, always, he has held out the prospect of success.

Seeking to build on this week's testimony by Army Gen. David H. Petraeus, U.S. commander in Iraq, and Ryan C. Crocker, U.S. ambassador to Iraq, Bush is planning to deliver another prime-time address to the nation tonight, on the eve of his delivery to Congress of a major report assessing the progress of the war.

Bush is expected to indicate his support for Petraeus' plan to slowly draw down the 30,000 troops sent to Iraq in the so-called surge, but leave a force of 130,000 into next summer.

The speech, to be delivered from the White House at 6:01 p.m. PDT, will be Bush's most visible effort to answer congressional pressure to begin a major withdrawal of troops. With Congress back from its summer recess, key decisions are looming on the administration's latest requests to pay for the war.

By midday Wednesday, White House speechwriters had gone through more than 20 drafts, White House Press Secretary Tony Snow said.

Bush is planning to follow tonight's speech with another Friday at the Marine Corps base at Quantico, Va. Vice President Dick Cheney is also scheduled to speak Friday before a military audience, at the Tampa, Fla., headquarters of the U.S. Central Command, which is responsible for U.S. military operations across the Middle East.

Whether speaking from an intimate, dignified setting in the White House or before a symbolic, photogenic backdrop provided by uniformed troops, Bush has sought to use his addresses to the nation to mark key moments.

On the deck of the returning aircraft carrier Abraham Lincoln, for example, barely six weeks after U.S. troops first crossed into Iraq, he declared an end to major combat operations after Saddam Hussein was overthrown.