Presumptive GOP presidential nominee Sen. John McCain (Ariz.) on Tuesday unveiled an overhaul of the GI bill to defend himself from veteran-group criticism and steal a bit of thunder from Sen. Jim Webb (Va.), a potential Democratic vice presidential candidate.

The move comes after McCain, a former Navy officer and prisoner of war, was heavily criticized by thousands of Iraq and Afghanistan veterans for not supporting Webb’s bill. The criticism was unusual for McCain, who has relied on his military credentials during the campaign.

Webb’s bill, which covers the full cost for veterans to attend a state university, also has the support of Sen. John Warner (R-Va.), McCain’s predecessor as top Republican on the Senate Armed Services Committee. Webb had been pressing McCain to sponsor his bill for weeks, but McCain refused.

Sen. Lindsey Graham (R-S.C.), a close ally of McCain’s and co-sponsor of the bill, told The Hill it is not meant to compete with Webb’s measure.

“I hope we can just have a marrying of interests,” Graham said. “We need to get this done.”

At the same time, McCain and other supporters of the new bill touted it as an improvement over Webb’s measure. Some military officials have worried the Webb bill’s wouls provide such an incentive for active-duty military to attend school that it would make it hard for the military to retain soldiers.

Senate Majority Leader Harry Reid (D-Nev.) blasted the GOP bill as a “pale shadow” of the Webb measure, and criticized McCain for having “no problem spending $12 billion a month on an open-ended civil war in Iraq.” He said the McCain bill would shortchange veterans.

The McCain-sponsored bill aims to increase the $1,100 per month active-duty service members now get for educational expenses to $1,500. The sum would increase to $2,000 per month for a member who served on active duty 12 years or more.

In addition, under the McCain bill, members of the military could transfer half their benefits to their spouses and children if they serve for six years and all of their educational benefits if they serve 12 years.

Members of the National Guard and Reserves who have been called to active duty since Sept. 11, 2001, would receive $1,200 a month, an increase from $880.

Those who have entered the military through the Reserve Officers Training Corps programs at universities across the country would also be eligible if they continue to serve past their ROTC commitments, and would also be eligible to transfer benefits to their families. Graham said this would keep larger number of officers in the military.

“We should encourage service members to remain in the military, and they should be rewarded with additional benefits if they do,” McCain said in a release announcing his proposal.

Webb’s bill is the top legislative priority for several veterans’ groups, including the nonpartisan Iraq and Afghanistan Veterans of America (IAVA). Its projected cost to the federal treasury is about $4 billion per year.

Webb has argued his bill is necessary because the current GI bill cannot pay for today’s cost of higher education.

The most a veteran can receive now is approximately $9,600 per year for four years. Those who served combat tours with the National Guard or Reserves are eligible for even less — typically just $440 per month, or $5,280 a year.

By contrast, the College Board reports that the average four-year public college costs more than $65,000, or about $16,250 a year, for an in-state student. A private university costs on average about $133,000 for four years.

McCain and Graham have criticized the Webb bill as difficult to administer, and as hurting military retention.

Webb countered that assertions that his bill is too difficult to administer and too generous and would harm services’ retention “are wrong.”

“S. 22 is hardly too generous, unless these senators are prepared to say that the World War II GI Bill was too generous,” Webb said in a statement. “To the contrary, during 15 months of daily cooperation with all of our major veterans’ groups and many members of Congress, we have refined this legislation in many important ways. It is our best collective, bipartisan effort to mirror the type of benefits given to those who served in World War II.”

Statistics show that up to 75 percent of Army soldiers and Marines who enlist return to civilian life at or before the end of their first enlistment.  

“The military is already doing a very good job of managing its career force,” Webb said in a statement. “It is not doing a very good job of assisting this large group of people as they attempt to readjust to civilian life. A good GI Bill will increase the pool of people interested in serving, lower first-term attrition, and would have a negligible effect on retention itself.”

Walter Alarkon contributed to this story.