Clinton’s VP Choices
Kaine has the relevant experience and preparation to be president that the other two simply don’t have, but choosing him would not be the attention-grabbing or “exciting” one that selecting one of the others would be. Having Kaine on the ticket would show seriousness about governing, and having someone prepared to take over in an emergency would be the responsible thing to do.
.. Taking Warren out of the Senate would be a mistake for Democrats, since that is where she is likely to have the greatest impact on the party’s agenda. Picking Warren would be seen as a concession to Sanders supporters, but the effect of it would be to make her a defender of whatever Clinton chose to do. Progressives would probably rather have her in the Senate acting as a critic of Clinton’s policies than as the person assigned the task of selling those policies to the left.