Aug. 11 (Bloomberg) -- President George W. Bush and his defense and foreign policy advisers meet at the president's ranch today facing a dilemma on Iraq, with pressure to start bringing troops home balanced against the risk of destabilizing the new government if the U.S. withdraws too soon.

The administration has settled on a ``rolling target'' for troop reductions as the Iraqis approach another political milestone next week by drafting a constitution, according to administration officials and defense analysts.

``We can't ramp up because we don't have the forces,'' said Loren Thompson, of the Lexington Institute, a defense policy research group in Arlington, Virginia. ``That leaves two choices: we stick it out for years to come or come up with some excuse to draw down our forces'' he said. ``It is abundantly clear that the Bush administration wants out.''

Bowing to U.S. demands, Iraq's interim government has vowed to meet an Aug. 15 deadline for a draft constitution, an October referendum and a December general election. With those dates on the calendar and continued efforts to train Iraqi security forces, the Pentagon is forming plans to cut the number of troops in Iraq to 100,000 by mid-2006 after raising the number to 160,000 from the current 138,000 for the elections.

``We are going to have a rolling target'' for troop reductions that lets U.S. forces withdraw as Iraqi units are able to take over security, White House Counselor Dan Bartlett said. ``What has been coming out of the Pentagon has been very carefully discussed in terms of a conditions-based strategy.''

Iraqi Abilities

Pentagon officials stress that any troop reduction will depend on the Iraqi government's ability to cope with a stubborn insurgency that has intensified in recent weeks. Bartlett said there has been no discussion about a complete withdrawal.

Michael O'Hanlon, an analyst at the Brookings Institution, a Washington-based policy research organization, said the administration is ``trying hard to send the message that we are hoping to get out in large numbers next year'' while keeping the president's commitment to stay in Iraq until the country is secure and has a democratic government.

Bush is meeting today with Defense Secretary Donald Rumsfeld and Secretary of State Condoleezza Rice. White House spokesman Trent Duffy said yesterday that U.S. troop levels and political progress in Iraq would be among the topics discussed.

The political stakes are high for Bush. With Republicans trying to maintain control of Congress in U.S. elections 16 months from now, U.S. public support for Bush's handling of the war is at its lowest level. Fifty-nine percent of adults said they disapproved of the way the president is handling Iraq in an Associated Press/Ipsos Public Affairs poll conducted Aug. 1-3.

Military Concerns

On top of political concerns, Bush must grapple with military and strategic considerations in Iraq. Continuing to burden already-stretched U.S. forces poses risks, according to experts such as Lynn Davis, a senior analyst at the Santa Monica, Calfornia-based RAND Corp., which conducts research for governments and businesses.

More frequent combat tours in Iraq are hurting U.S. military preparedness, a RAND study published last month concluded. ``The challenge the Army faces is profound,'' Davis, lead author of the report, said in an interview.

``The longer this goes on the more of a challenge it is,'' said Representative Vic Snyder, of Arkansas, the ranking Democrat on the House Armed Services Subcommittee on Personnel. ``We are concerned the rotation schedule is such that there isn't time for troops to get rested and trained.''

Troop Strains

Air Force General Richard Myers, chairman of the Joint Chiefs of Staff, said the U.S. military isn't yet in danger of running out of eligible National Guard and Army Reservists. There are no plans to ask Congress to let the Pentagon extend service limits on those troops.

``We look out several years and we think we will be able to fulfill what we think to be a worst case,'' Myers said in an interview.

The Pentagon will face a strain sooner than that, said Lawrence Korb, a former assistant secretary of defense for readiness in the Reagan administration.

``If you want to keep the same number of ground troops there a year from now, you are going to have to do things that will destroy the all-volunteer Army,'' Korb said. ``The military guys are really worried about the future of the Army.''

`Difficult but on Schedule'

Any drawdown of U.S. forces relies on assurances to the White House by U.S. Ambassador to Iraq Zalmay Khalilzad that ``the constitutional process is going to be difficult but on schedule,'' Bartlett said. Bush ``is still pleased with the trajectory we have in Iraq in terms of progress on security and the politics.''

The U.S. plans to have about 275,000 trained and equipped Iraqi security forces by June 2006, including regular army troops, specialized commandos, border guards and police. Critics, such as Senator Joseph Biden of Delaware, senior Democrat on the Foreign Relations Committee, say the number of Iraqi forces able to fight without help from U.S. troops is a fraction of that.

The U.S. presence also affects the political situation in Iraq, said Anthony Cordesman, a Middle East security analyst at the Center for Strategic and International Studies in Washington. ``Unless the U.S. can be seen moving down and getting out, the legitimacy of the Iraqi government is uncertain, and pressure from the Shiite side is going to steadily increase for U.S. withdrawals,'' he said.

Withdrawal Risks

Pulling out too many troops too fast may embolden the insurgents to step up their attacks on the new Iraqi government or allow the friction among Shiites, Sunnis and the Kurds to spark a civil war.

``We are going to need somewhere between 50,000 and 60,000 troops'' in Iraq ``permanently,'' said John Pike of GlobalSecurity.org, an Alexandria, Virginia-based defense research group. ``That would guarantee of the integrity of this little government we have set up.

The past two weeks have been one of the deadliest periods for the U.S. military in Iraq, with at least 44 soldiers and Marines killed by insurgents. At least 1,839 U.S. military personnel have died in Iraq since the March 2003 invasion.

Iraq ``has become a conflict that we can't win,'' said James Dobbins, director of the International Security and Defense Policy Center at RAND.

Pentagon officials say handing control to the Iraqis and not defeating the insurgency is the goal in Iraq.

``The Iraqis are going to have to defeat the insurgency and it will probably be a process of years,'' said Army Lieutenant Colonel Barry Venable, a Pentagon spokesman.

To contact the reporters on this story: Bill Roberts in Washington at wroberts@bloomberg.net; Jeff St.Onge in Washington at jstonge@bloomberg.net

Last Updated: August 11, 2005 00:29 EDT