WASHINGTON, Dec. 31 (UPI) -- The crisis afflicting the U.S. Air Force's F-15 domestic defense fleet is far wider, more serious and more deeply rooted than the American public seems to realize. It is rooted in more than 15 years of systematic neglect of U.S. air power by Republicans and Democrats alike.

The U.S. Air Force moved quickly to pull some 450 old McDonnell-Douglas F-15 fighter aircraft after one of them crashed in Missouri on Nov. 2. USAF investigators concluded that there were significant defects in the metal framework that held the body of the plane together. Because the problem was caused by excessive wear and tear on the fuselage of the plane over its decades of service, the USAF team warned this could cause "fleet-wide airworthiness problems." Even now, the entire grounded F-15 force has not been cleared for active duty, and it remains an open question if and when that will happen.

The Air Force is filling the gap by pressing its other old workhorse, the F-16 Falcon fleet, into increased duty. But that can only hasten the day when accumulated stress and wear problems become a serious issue for it, too. Meanwhile, the crisis is forcing the U.S. Air National Guard into emergency deployments that has forced the California Air National Guard, for example, to take over responsibility for air defense and interception duties over Oregon and Washington as well. The Vermont ANG has been forced to assume similar responsibilities over the northeastern United States.

After the huge increases in military and Air Force procurement and spending during the Reagan administration, the collapse of communism at the end of 1991 seemed to usher in a "peace dividend" for the rest of the 1990s. Defense spending, already slashed when President George Herbert Walker Bush was still in the White House, was cut even further by Democratic President Bill Clinton during his two terms of office.

The United States fought no major wars during the Clinton era, but the Air Force was involved especially in major logistics operations and bombing campaigns in the brief Kosovo conflict in 1998 and in maintaining the U.S.-brokered end of the conflict in Bosnia in 1995. Wear and tear on the aging USAF fleet, especially its transport aircraft, was already a serious consideration by the time of the 2000 presidential election campaign. Indeed, George W. Bush and Dick Cheney campaigned on the promise of restoring needed funding to the over-stretched Air Force.