[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2008/images/08/04/art.obama.iraq.jpg
caption="Obama met with Gen. Petraeus while visiting Iraq last month."]
WASHINGTON (CNN) - As speculation over the number two slot rises, presidential candidate Barack Obama and potential v.p. contender Sen. Evan Bayh of Indiana joined forces Monday, signing a letter with eight other senators that urges Defense Secretary Robert Gates to increase medical coverage and care for Iraq war veterans left with serious brain injuries.
The senators point to a recent study from the RAND Corporation that estimates 320,000 troops from the two Iraq wars experienced a traumatic brain injury, or TBI.
"We are concerned that at a time when TBI is recognized as the signature wound of the conflicts in Iraq and Afghanistan," the senators write, "one of the most widely accepted and critical rehabilitative treatments for this injury… cognitive rehabilitation therapy, is excluded by the military's … health insurance program."
The other senators signing on to the letter include political notables Sen. Hillary Clinton, D-New York, Sen. Ted Kennedy, D-Mass, Sen. John Kerry, D-Mass and Sen. Joe Lieberman, D-CT. Obama and Bayh's name are clearly perched at the top.