WASHINGTON - In a first-day whirlwind, President Barack Obama showcased efforts to revive the economy on Wednesday, summoned top military officials to the White House to chart a new course in Iraq and eased into the daunting thicket of Middle East diplomacy. "What an opportunity we have to change this country," said the 47-year-old chief executive, who also issued new ethics rules for his administration, hosted a reception at the presidential mansion for 200 inauguration volunteers and guests selected by an Internet lottery and even took the oath of office again after it was flubbed Tuesday.

After dancing at inaugural balls with first lady Michelle Obama past midnight, Obama entered the Oval Office for the first time as president in early morning. He read a good luck note left behind by President George W. Bush, then began breaking cleanly with his predecessor's policies.

Aides circulated a draft of an executive order that would close the detention facility at Guantanamo Bay, Cuba, within a year and halt all war crimes trials in the meantime.

Closing the site "would further the national security and foreign policy interests of the United States and the interests of justice," read the draft prepared for the new president's signature. A copy was obtained by The Associated Press, and an aide said privately that Obama would sign a formal order on Thursday.

Some of the 245 detainees currently held at Guantanamo would be released, while others would be transferred elsewhere and later put on trial under terms to be determined.

Obama's Cabinet was moving closer to completion.

At the Capitol, the Senate confirmed Hillary Rodham Clinton as secretary of state after a one-day delay forced by Republicans. The vote was 94-2, and spectators seated in the galleries erupted in applause when it was announced.

Treasury-designate Timothy Geithner emerged unscathed from his confirmation hearing, apologizing for having failed to pay $34,000 in taxes earlier in the decade.

To the evident anger of Sen. Patrick Leahy, D-Vt., chairman of the Senate Judiciary Committee, Republicans on the panel invoked longstanding rules to postpone a vote on Eric Holder's appointment as attorney general.

Counting Clinton, seven Cabinet members have been confirmed so far, as have the two top officials at the Office of Management and Budget.

Obama's schedule for the day included separate sessions on the economy and the wars in Iraq and Afghanistan.

The new president has pledged to take bold steps to revive the economy, which is struggling through the worst recession since the Great Depression. Last week, he won approval to use $350 billion in leftover financial industry bailout funds.

He presided over the White House meeting on the economy as the House Appropriations Committee moved toward approval of $358 billion in new spending, part of the economic stimulus package making its way to his desk.

The new commander in chief held his first meeting in the Situation Room, where he, Vice President Joe Biden and senior military and foreign policy officials discussed war in Iraq and Afghanistan. Obama campaigned on a pledge to withdraw U.S. combat forces from Iraq within 16 months, and to beef up the commitment in Afghanistan. Obama asked the Pentagon to do whatever additional planning necessary to "execute a responsible military drawdown from Iraq."

The new White House press secretary, Robert Gibbs, said Obama's phone calls to leaders in the Middle East were meant to convey his "commitment to active engagement in pursuit of Arab-Israeli peace from the beginning of his term."

Gibbs also that in conversations with Israeli, Palestinian, Egyptian and Jordanian leaders, the president emphasized he would work to consolidate the cease-fire between Israel and Hamas in Gaza.

Obama intends to name former Senate Majority leader George Mitchell as a special envoy to the region.

Not everything was new at the White House.

In the Oval Office, Obama worked at a desk built from the timbers of a British naval vessel, the HMS Resolute, and used off-and-on by presidents since the 1870s, including Bush. It also appeared that the carpet that Bush used in his second term, a yellow sunbeam design, was still in place.

If some of the furnishings remained in place, there was no doubt that the new president meant to fulfill his campaign promise of change.

"As of today, lobbyists will be subject to stricter limits than under any ... other administration in history," Obama told reporters as he signed the new rules. The restrictions included a ban on gifts by lobbyists to anyone serving in the administration.

He also imposed a pay freeze for about 100 White House aides who earn $100,000 or more. Its implementation was unclear, since none of them was on the payroll before Tuesday's noontime inauguration.

On Tuesday, within hours of Obama's inauguration, his administration froze last-minute Bush administration regulations before they could take effect.

Among them was an Interior Department proposal to remove gray wolves from Endangered Species protections in much of the northern Rocky Mountains, and a Labor Department recommendation that would allow companies that manage employee retirement plans to market investment products to plan participants.

On Wednesday night, Chief Justice John Roberts administered the oath to Obama at the White House _ a rare do-over. The surprise moment came in response to Tuesday's stumble, when Roberts got the words of the oath a little off, which prompted Obama to do so, too.

The White House reassured that Obama has still been president since noon on Inauguration Day. But Obama and Roberts went through the drill again out of what White House counsel Greg Craig called "an abundance of caution."

Obama and his wife began their day at a prayer service that is traditional for the first business day of a new administration. They were joined in front-pew seats by Biden and his wife, Jill, as well as former President Bill Clinton and his wife, hours away from confirmation as the nation's top diplomat.

"Grant to Barack Obama, president of the United States, and to all in authority your grace and good will. Bless them with your heavenly gifts, give them wisdom and strength to know and to do your will," prayed the Rev. Andy Stanley, one of numerous clerics from several religions to speak.

Obama and his wife also played host and hostess for a select 200 at an open house.

"Enjoy yourself, roam around," a smiling Obama told one guest.

"Don't break anything."