Sen. Chuck Hagel is a Vietnam vet and a Republican, Sen. Jim Webb is also a Vietnam vet and a Democrat, and they proposed a new GI Bill to support the troops fighting in Iraq, similar to the GI Bill that came about after World War II.
The Bush administration is against it, so the threat of a veto makes it impossible to pass with just Democratic support in the Senate. The bill would therefore need 60 sponsors to be "veto-proof," and that means Republicans like John McCain would need to sign on. But most Republicans, including McCain, have refused.
McCain's reasons were in today's NY Times Magazine:
"...When Webb and Hagel (a close personal friend of McCain’s) proposed a bill to give troops leaving Iraq and Afghanistan more time at home before redeploying, McCain, whose 19-year-old son has served with the Marines in Iraq, forcefully opposed them, saying the troops were needed in the theater. More recently, McCain has found himself on the opposite side of Webb and Hagel again, this time over their “G.I. bill” that would offer education money to every returning veteran. McCain and others want a more limited bill that would encourage rank-and-file soldiers to re-enlist rather than return to civilian life."
Also in that same article today:
"...In his book, Chuck Hagel writes of listening to declassified tapes from the mid-1960s in which Lyndon Johnson admitted to advisers that Vietnam probably couldn’t be won but rued that withdrawal would make him the first American president to lose a war. “I wish someone had told me when I was sitting on a burning tank in a Vietnamese rice paddy that I was fighting for a lost cause just to save a president’s legacy,” Hagel observes acidly."