Fuselage: Made of high-strength reinforced aluminum alloy, it can withstand crash impacts in excess of 15 Gs.

Engine: The VH-71 can shift from three 3,000-horsepower turboshaft engines to two, whereas the twin-engine Sea King must land if one engine fails.

Rotor: Five flared rotor blades increase the craft's efficiency by up to 30 percent over conventional designs when flying at 150-knot cruising speed.

Defense System: The VH-71s, like the EH101s they are modeled on, will probably feature radar-warning receiv-ers, laser detectors and flare dispensers to deflect anti-aircraft missiles.

Cabin: Measuring eight feet wide and 25 feet long, the cabin will include a lavatory and a galley kitchen. The fold-down stair spares the president from ducking during photogenic entrances and exits.

Communications: More room for communications hardware means the president will have secure and continuous access to all White House and Pentagon computer systems and data streams.

"It is a challenging political environment," acknowledges Tracey Schmitt, a spokeswoman for the Republican National Committee, "but we are confident that ultimately voters in November will recognize that a Democrat Congress would simply not be equipped to ensure either economic or national security for our nation."

Bush's fall is being fueled by erosion among support from conservatives and Republicans. In the poll, 52% of conservatives and 68% of Republicans approved of the job he is doing. Both are record lows among those groups.

Moderates gave him an approval rating of 28%, liberals of 7%.

"You hear people say he has a hard core that will never desert him, and that has been the case for most of the administration," says Charles Franklin, a political scientist at the University of Wisconsin who studies presidential approval ratings. "But for the last few months, we started to see that hard core seriously erode in support."

Only four presidents have scored lower approval ratings since the Gallup Poll began regularly measuring it in the mid-1940s: Harry Truman, Richard Nixon, Jimmy Carter and the first George Bush. When Nixon, Carter and the elder Bush sank below 35%, they never again registered above 40%.

Truman twice sank into the low 30s and then rose into the 60s, but the third time his rating fell, it stayed below 40% as well.

"Historically it's been pretty devastating to presidents at this level," Franklin says. Even Republican members of Congress are "now so worried about their electoral fortunes in November that he has less leverage with them than he normally would with his own party controlling Congress."

In a motion filed Friday but released Monday, Moussaoui said he testified on March 27 that he was supposed to hijack a fifth plane on Sept. 11, 2001, and fly it into the White House "even though I knew that was a complete fabrication."

A federal court jury spared the 37-year-old Frenchman the death penalty last Wednesday. On Thursday, Brinkema gave him six life sentences, to run as two consecutive life terms, in the federal supermax prison at Florence, Colo.

Explaining his latest reversal, Moussaoui said in an affidavit: "I was extremely surprised" by the life sentence.

"I had thought I would be sentenced to death based on the emotions and anger toward me for the deaths on Sept. 11, but after reviewing the jury verdict and reading how the jurors set aside their emotions and disgust for me and focused on the law and the evidence ... I now see that it is possible that I can receive a fair trial even with Americans as jurors."

At sentencing, Brinkema told Moussaoui, "You do not have a right to appeal your convictions, as was explained to you" when he pleaded guilty in April 2005. "You waived that right," she said.

Brinkema said Moussaoui could appeal his sentence but added, "I believe it would be an act of futility."

Moussaoui's court-appointed lawyers told the court that they filed the motion even though a federal rule "prohibits a defendant from withdrawing a guilty plea after imposition of sentence." They did so anyway, they said, because of their "problematic relationship with Moussaoui" and the fact that new lawyers have yet to be appointed to replace them.

The defense lawyers were not immediately available for comment Monday. Brinkema said they would be replaced after they filed any appeal Moussaoui might want.

The motion said Moussaoui told his lawyers Friday that he wanted to withdraw his guilty plea because when he entered it his "understanding of the American legal system was completely flawed."

In an attached three-page affidavit, Moussaoui cited his new opinion of American jurors and wrote that he now believes he has a fair chance "to prove that I did not have any knowledge of and was not a member of the plot to hijack planes and crash them into buildings on Sept. 11, 2001."

"I wish to withdraw my guilty plea and ask the court for a new trial to prove my innocence of the Sept. 11 plot," Moussaoui wrote. "I have never met (lead 9/11 hijacker) Mohammed Atta and, while I may have seen a few of the other hijackers ... (in Afghanistan), I never knew them or anything about their operation."

Explaining his twists and turns, Moussaoui said, "Solitary confinement made me hostile toward everyone, and I began taking extreme positions to fight the system."

Moussaoui said that, coupled with his inability to get a Muslim lawyer, led him to distrust his lawyers when they told him he could be convicted of being an al-Qaida member but acquitted of involvement in 9/11.

Moussaoui wrote that he pleaded guilty because he mistakenly thought the Supreme Court would immediately review his objection to being denied the opportunity to call captured enemy combatant witnesses to buttress his claim of not being involved in the 9/11 plot.

An appeals court agreed with the government that national security would be at risk if captured operatives like 9/11 mastermind Khalid Shaikh Mohammed testified or were even questioned by Moussaoui's lawyers. Instead, statements taken from their interrogations were read to the jury.

Shaikh Mohammed's statements said Moussaoui was never considered for the 9/11 plot, only a later attack.

Moussaoui shocked the courtroom at his sentencing trial when he recanted his four-year-old claim of having nothing to do with 9/11. When he pleaded guilty in 2005, he had explained that he was to hijack a 747 jetliner and fly it into the White House at some later date if the United States refused to release a radical Egyptian sheik who is serving a life term for terrorist acts in New York.

But when he testified, Moussaoui claimed that the 747 was to be a fifth plane hijacked on Sept. 11 and that Richard Reid, now imprisoned for a December 2001 shoe bombing attempt aboard a trans-Atlantic flight, was to be on his hijacking team.

That testimony revived the government's flagging case in the first part of the sentencing trial.

On April 3, the jury found Moussaoui eligible for the death penalty. It apparently accepted prosecutors' arguments that by withholding information from federal agents who arrested him on Aug. 16, 2001, he bore responsibility for at least one death on 9/11 by preventing the agents from identifying and stopping some hijackers.

Nevertheless, the same jury was unable to unanimously find that Moussaoui, who was in jail on 9/11, deserved execution. Three jurors wrote on the verdict form that they doubted he knew much about the 9/11 plot.

After Moussaoui's testimony, his lawyers made clear in court that they thought he was lying to achieve martyrdom through execution. Prosecutors even stipulated that the government doubted Moussaoui's claim that Reid was part of his team. And the judge told lawyers, out of the jury's hearing, that she doubted his testimony about how much he knew about the 9/11 plot.