In his opening statement today, McCain challenged the comprehensiveness of the report, saying only a quarter of the armed services were surveyed. The report, he said, "does not lead to one unequivocal solution."
He also said he wanted to make sure the debate is "focused on the military and its effectiveness, not broad social issues being debated in our society." McCain has earlier this week questioned the military experience of those supporting repeal -- who include those testifying today, Defense Secretary Robert Gates, Chairman of the Joint Chiefs of Staff Adm. Michael Mullen and the co-chairs of the review, Gen. Carter Ham, who is on tap to become the next commander of AFRICOM, and Jeh Johnson, the department's general counsel.
Mullen subtly shot back at McCain during his own opening statement, noting that while he isn't directly in charge of troops as the Joint Chiefs Chairman, he has commanded several ships, fleets, and U.S. Naval Forces in Europe.
During his first round of questioning, McCain quizzed Gates on why larger numbers of combat troops predicted a negative impact from repealing Don't Ask, Don't Tell.
Gates told him that combat troops are generally young, between 18 and 25, and have limited military experience in which they haven't even served with women. The time they have served, he said, has been a difficult time -- one on the front lines of war.
"I couldn't disagree more," McCain shot back. "If they're mature enough to fight and die, they're mature enough" to form an opinion on who they want to serve with. "I'm speaking from personal experience," he said.
Gates noted that those combat troops who had served with a gay colleague were much more open to the idea of repeal.
McCain has said over the years that he would support repeal if the top military brass support it.