He graduated first in his class at University of Texas law school and clerked for Rehnquist (although Nixon may have pulled some strings to get Rehnquist to take him). Now he's a partner in a law firm with his name in it. He is by all accounts an extremely competent and successful lawyer.
He's the perfect political operative: he's a man of honor and skill, who understands politics and how to make a case in a courtroom (how to put arguments together). He's tough enough that he can go on Nightline and duke it out with Ted Koppel. He's got enough charisma to get hundreds of Swift Vets and POWs to join him. And he's not a sleazeball like most political ops, so he isn't going to shoot himself in the foot. He also has ZERO loyalty to George W. Bush, his only goal is taking down Kerry (that sort of focus is imporant for his integrity).
We're not going to see another "Swift Vets"-type group for a long time. They are something special.
Unfortunately, he has said that he voted for Gore and that he would have voted for Edwards had the Breck Girl gotten the nomination.
While I think Mr. O'Neill is doing the Lord's work here, do not make the mistake that he is an "ally."