WASHINGTON (AP) - John McCain and Barack Obama vow to reform the nation's defense procurement if elected president, yet each is unwilling to take a firm stand against the skyrocketing cost of a plum White House perk: the new Marine One helicopter.

Originally carrying a hefty price tag at $6.1 billion, the fleet of 28 helicopters being built to fly the next president is now projected to cost $11.2 billion.

At $400 million apiece, the helicopters far exceed a prime example McCain uses on the campaign trail to rail against congressional pork-barrel spending, a $230 million "bridge to nowhere" in Alaska. The British have bought the same base model helicopter for $57 million each.

In separate interviews with The Associated Press, the Republican and Democratic presidential candidates pledged to look at the program but stopped short of saying whether it should be canceled. Any review after the next president takes office in January would butt up against the first deliveries of the helicopters, slated for 2010.

McCain labeled the contract growth a "scandal" before asking to revise his assessment "in a more polite way." He said the program is part of "an out-of-control procurement system that has to be fixed."

Obama said, "I haven't taken a close look at it, but, in principle, it is a lot of money, even in Washington."

Asked whether the president needed such a large and expensive fleet of helicopters for his most common trip, a 10-minute flight to and from Andrews Air Force Base, Obama said: "Here's what I know: that we should be spending a lot more money trying to figure out how to get our energy policy right than we should be on helicopters for the president. I have not examined in detail this proposal, and since you brought it up, I'll take a close look at it."

Congress and the Pentagon are already reviewing the program to determine how to cope with the contract growth. In an audit, the Government Accountability Office has also raised concerns about the helicopter's weight and its new rotor system.

The program has its roots in the Sept. 11, 2001, terrorist attacks. After the attacks, President Bush flew on Air Force One, a customized Boeing 747, from Florida to military bases in Louisiana and Nebraska before returning to Washington. The chaos of that day underscored the need for secure communications and the commander in chief's ability to remain in contact at all times.

Some of the existing fleet of 19 presidential helicopters, any of which is known as "Marine One" when the president is aboard, are more than 30 years old. Several have broken down on presidential trips, a concern that prompted then-White House Chief of Staff Andrew Card to begin the replacement process in 2002.

In 2005, the Pentagon awarded the contract, itself a subject of controversy. Connecticut-based Sikorsky Aircraft, which had always supplied helicopters for the president, was beaten in the bidding process by Lockheed Martin. The Maryland-based firm proposed a variation of a European helicopter built by Agusta-Westland.

Since then, the contractor has complained the Navy has added 1,900 requirements that have driven up the cost. A swift development schedule has production starting while design is still underway. Pentagon officials insist the contract has not been changed since it was signed.

The current plan calls for fielding five helicopters, which will then be replaced by a fleet of 23 more once equipment and design issues are resolved.

White House and Pentagon officials say the president needs so many because he can make several stops in a day requiring helicopter travel. Pilots in the elite HMX-1 Marine division also train constantly in the aircraft and fly other dignitaries, including the vice president, defense secretary and foreign heads of state.

And as can be witnessed by tourists on the National Mall near the White House, several of the identically marked helicopters often accompany Marine One in flight as decoys.

McCain, a former Navy pilot, has promised to review all military programs with the aim of reforming defense procurement. He argues he saved taxpayers $6.2 billion program by scuttling an Air Force plan to lease aerial refueling planes from Boeing. Two company executives, one of them a former Air Force procurement official who helped negotiate the tanker lease before being hired by Boeing, went to jail over the deal. Boeing's chief executive officer subsequently stepped down.

"I'm talking about a broken system in Washington, and the helicopter is a visible manifestation of a very serious problem we have of overspending," McCain said. "So, all I can say is it's also going to be the responsibility of the president to get defense procurement fixed and give the taxpayers a reasonable return on their defense dollar."

Should the contract be halted?

"The helicopter? Should it be stopped?" the Arizona senator said to the AP as his "Straight Talk Express" campaign bus rolled through Ohio. "I haven't gotten an update on it recently enough to know it. But it's certainly an unacceptable situation with costs overruns."

Obama said the cost growth is an example "of some of the systemic problems that we have in Pentagon procurement."