Even Andrew Sullivan is throwing the idea of Hillary as VP on the table. His take is that it could be a Lincolnesque Team of Rivals move, that could reinforce Obama's conciliatory message.

My view is that they are not rivals. At least, not the type of rivals that would hammer out more reasoned policy, as was the intent with Lincoln.

Clinton and Obama are rivals in the sense of political tactics only. As has been discussed thoroughly, their policy differences are slight. But there approach to political tactics is mutually exclusive. And this is the one area that Obama should not compromise. It is the central argument to his campaign: that our current political discourse is crippling Washington. Clinton does not believe this at all. She believes the only problem is that the Republicans are in power. If she were VP, these stances would collide and destroy Obama's effectiveness in bridge building.

Am I saying Hillary can't work with Republicans? No. Clearly she has on a few issues. But overall, she believes that political perception is the most important component of a politician. Obama believes that the ability to present a reasoned pragmatic policy is the most important. One example: Iran. Clinton is all for talking tough to Iran, even though she is not actually a hawk, simply because she has conceded foreign policy strength to the Right. Obama has a much more pragmatic approach, but one that's politically radical. If you ask either of them which is more pragmatic and reasoned, each will say theirs is. Clinton's because it is politically "center" (triangulation in full effect). Obama's because it is a more reasoned approach, absent of hysteria (but outside the political mainstream). I believe that Clinton actually agrees with Obama, but wouldn't admit for fear of being perceived as weak on defense.

Another example is gas tax suspension. Clinton is extremely bright and obviously does value the opinion of economists. But, in this case, political perception was more important. It polled well, and Obama's position didn't, initially. What happened? Obama actually shaped public opinion on this issue. What began as politically risky, ended as the right move politically. This is why Obama is more effective than Hillary.  If she were his VP and advisor, she would have steered him away from principle and toward the political. That would've diluted his message, and hurt his chances.

If Obama wants to pick a rival for VP, and I think he should, it should be a rival on policy, not on politics. It needs to be someone who clashes with Obama on principle, but not on political philosophy. That way the people know that what comes from the administration is principled, reasoned, and agreed on by those on both sides of the issue, regardless of political consequences.

Who fits this mold? Actually, the old McCain comes to my mind, but oh well. I think it would have to be a hawkish Dem or Republican with a reputation for being civil and classy. Hagel, Feinstein, Lugar, Snowe... Powell?