WASHINGTON – Weary but determined, President Bush on Wednesday returned from his surprise visit to Baghdad with newfound confidence in the fledgling Iraqi government as he restated his determination that American troops would not leave the country until their mission has been completed.

Appearing at a Rose Garden press conference only hours after flying home through the night, Bush said the secrecy-shrouded trip left him convinced that the survival of Prime Minister Nouri al-Maliki’s government is critical to American security.

“That’s why one message that I will continue to send to the enemy is: Don’t count on us leaving before the mission is complete,” said the jet-lagged president. “Don’t bet on American politics forcing my hand because it’s not going to happen. I’m going to make decisions not based upon politics but based upon what’s best for the United States of America.”

With Democratic-stoked pressures building in Congress to establish a timetable for withdrawing the 130,000 U.S. troops now in Iraq, Bush seemed eager to plunge into a developing election year debate, saying, “I will remind the American people if we pull out before we achieve our objective, the world will be a lot more dangerous and America will be more at risk.”

Bush called reporters to the White House on short notice in an apparent effort to stoke the positive momentum generated by last week’s killing of Abu Musab al-Zarqawi, the leader of the insurgent group al-Qaida in Iraq; Maliki’s success in completing a coalition government in Baghdad, and the news that his key aide, Karl Rove, would not be subject to criminal prosecution in the leak of a CIA operative’s name.

But he also seemed to exhibit a keen awareness that his political clout remains hostage to the kind of insurgent and sectarian violence in Iraq that in the past has played a powerful role in discouraging Americans about Iraq and, more generally, about Bush’s presidency.

“I hope there’s not an expectation that all of a sudden there’s going to be zero violence,” Bush said. “It’s not going to be the case.”

Admitting to jet lag after flying more than 20 hours to and from Iraq in order to spend five hours in Baghdad’s Green Zone, Bush said he endured the ordeal to satisfy himself that Iraq now has the leadership to prevail after earlier governments seemed inadequate to the task.

Junking a plan to confer with Maliki and his government via a teleconference from the Camp David presidential retreat, Bush said, “One of the reasons I went to Iraq was to be able to sit down with an Iraqi government to determine whether or not they have the will to succeed.”

He added, “I’ve eliminated that uncertainty.”

Appearing buoyed by the trip’s outcome, the president teased one reporter for wearing “shades” or sunglasses and praised another’s neckwear. He noted that some news organizations had sent substitutes to the press conference and praised a question posed by one of the newcomers.

In an acknowledgment that the new Iraqi government’s success will rest in part on its ability to strengthen the country’s economy and restore basic services, he said, “My advice to them is to use their energy assets as a way to unite the country.”

He added: “You can measure progress in, you know, megawatts of electricity delivered. You can measure progress in terms of oil sold on the market on behalf of the Iraqi people.”

Carefully noting that his thoughts were only advisory, he said that he suggested to Maliki’s Cabinet that the government establish an oil “royalty trust,” similar to an arrangement used by Alaska to make sure that oil revenues benefit the entire country. One of the most divisive struggles within the Iraqi government involves attempts by the Shiite majority to maintain provincial control of those revenues at the expense of the Sunni minority concentrated in areas lacking energy resources.

Underscoring the administration’s desire to attract more international aid for Iraq, Bush said that Maliki is developing a “compact” under which foreign governments would boost their political and economic support in return for as yet unspecified Iraqi steps “in the political, economic and security areas.”

The president noted that foreign governments have pledged about $13 billion to aid the new Iraqi government but “they’ve only paid about $3 billion.” Reiterating his formulation that the American military would “stand down” only when Iraqi forces become capable of defending the country on their own, he praised Maliki’s plan to rein in sectarian militias that have infiltrated the security forces, saying “illegal militias have no future in a free Iraq.”

In response to a question about the U.S. image abroad, Bush said he would like to close the Guantanamo camp for war-on-terror detainees, noting that the facility has proven a magnet for international condemnation.

But he argued that the camp houses “dangerous” battlefield fighters and asserted that their cases would be heard in court.

With Bush’s flight shrouded in extraordinary secrecy, Maliki was informed about his guest’s arrival only minutes before they actually met.

Asked about the “signal” that might have sent to the new government, Bush noted, “I’m a, you know, a high-value target for some, and Iraq’s a dangerous place. And the American got to know that I will take precautions when I travel somewhere. I’m not going to put our government at risk.”

The violence in Iraq and the president’s trip there largely dominated the press conference. But on other matters, he brushed off a question about whether signs of mounting inflation pose a threat to the economy, saying that the issue falls under the jurisdiction of the Federal Reserve System.

He also praised the CIA leak investigation mounted by Special Counsel Patrick Fitzgerald and said that “the White House took a sigh of relief” when Fitzgerald notified Rove’s lawyer that his client would not be indicted. But he declined further discussion of the probe’s outcome, noting the pending criminal trial facing former vice presidential aide I. Lewis “Scooter” Libby.