Defense Secretary Robert Gates answers a question during a briefing at the Pentagon in Washington, Wednesday, April 11, 2007. [AP]

The change, announced Wednesday by Defense Secretary Robert Gates, is the latest blow to an all-volunteer Army that has been given ever-shorter periods of rest and retraining at home between overseas deployments.

Rather than continue to shrink the at-home intervals to a point that might compromise soldiers' preparedness for combat, Gates chose to lengthen combat tours to buy time for units newly returned from battle. The longer tours will affect about 100,000 soldiers currently in Iraq and Afghanistan, plus untold thousands more who deploy later. It does not affect the Marine Corps or the National Guard or Reserve.

"Our forces are stretched, there's no question about that," Gates said.

The extended tours are a price the Army must pay to sustain the troop buildup that

President Bush ordered in January as part of his rejiggered strategy for stabilizing Baghdad and averting a US defeat. Troop levels are being boosted from 15 brigades to 20 brigades, and in order to keep that up beyond summer the Army faced harsh choices: Either send units to Iraq with less than 12 months at home, or extend tours.

The decision also underscores the political cost the administration has had to pay in order to keep alive its hope that higher troop levels in Iraq, combined with a push for Iraqi political reconciliation, will finally produce the stability in Baghdad that experts say is needed before US troops can begin going home.

In recent days, the Pentagon has notified National Guard brigades from four states that they are in line to deploy to Iraq for a second time, eliciting complaints from governors. Also, the Pentagon poured more than $1 billion into bonuses last year to keep soldiers and Marines in the military in the face of an unpopular war.

At a Pentagon news conference, Gates said that it was too early to estimate how long the troop buildup would last but that his new policy would give the Pentagon the capability to maintain the higher force levels until next April. Democrats in Congress, and some Republicans, oppose the buildup and are trying to force Bush to change course. In January, the administration indicated the buildup might begin to be reversed by late summer or fall.

Reaction on Capitol Hill to Gates' announcement was harsh.

"Extending the tours of all active-duty Army personnel is an unacceptable price for our troops and their families to pay," said House Speaker Nancy Pelosi (news, bio, voting record), D-Calif.

Rep. Ike Skelton (news, bio, voting record), D-Mo., chairman of the House Armed Services Committee, said the longer tours will have a "chilling effect" on recruiting and the Army's ability to keep soldiers from quitting the service.

"We also must not underestimate the enormous negative impact this will have on Army families," Skelton said.

Sen. Lindsey Graham (news, bio, voting record), R-S.C., who supports the troop buildup, said of the affected soldiers, "They'll be disappointed, but they'll do it."

Indeed, at Fort Bliss, Texas, home of the 4th Brigade Combat Team, 1st Calvary Division, some Army families took the news in stride.

Carol Frennier, whose husband, Command Sgt. Maj. Steve Frennier, is in Iraq, said she had prepared herself and her family for a longer deployment.

"They kind of told us to expect 12 months to 18 months," she said. "We were already prepared to have them extended." And her family has been through an extended tour of duty before.

"Last time they said nine months, and it was 14 months," Frennier said.

Gates said that without making 15 months the standard tour length in place of the current 12, he would have been forced to send five active-duty Army brigades to Iraq before they completed their one year at home.

"I think it is fair to all soldiers that all share the burden equally," he said.

Anthony Cordesman, an Iraq watcher at the Center for Strategic and International Studies, said Gates faced little choice, with the strains already on the Army and no certainty about when the war might end.

"You've got to do it," Cordesman said of the tour extensions, if the Bush plan is to have a chance to succeed.

The longer tours do not apply to the National Guard or Reserve, nor to the Marines, who comprise about 25,000 of the 145,000 troops in Iraq. The Marines are sticking to their standard seven-month tours, with an average of seven months at home between tours, although some units have had their tours lengthened recently.

Gen. Peter Pace, the Joint Chiefs chairman who appeared at the news conference with Gates, acknowledged that longer tours in Iraq and Afghanistan make life harder for many soldiers.

"Is it an additional strain to go from 12 months to 15 months? Of course it is," Pace said. "Is it in combat and therefore even more difficult? Of course it is. And that's why the entire nation should be thankful that we have such incredible young men and women who, knowing that, who volunteer to serve this nation in a time of great need."

In an indication of the Pentagon's concern about how hard the news would hit Army families, Gates angrily denounced a news leak of his announcement. "I can't tell you how angry it makes many of us" that the leak denied the Army the ability to give families 48 hours notice, as planned, Gates told reporters.

"This policy is a difficult but necessary interim step," Gates said, adding that the goal is to eventually return to 12 months as the standard length of tour in Iraq and Afghanistan. As recently as February, senior Army leaders were telling soldiers they remained hopeful that tour lengths could be shortened to nine months or six months.

Gates said the new policy seeks to ensure that all active-duty Army units get at least 12 months at home between deployments.