Like most presidential nominees, Hillary Clinton said that, in contemplating her choice of a running mate, she was looking for the most qualified person to take over the presidency if necessary. In picking Sen. Tim Kaine of Virginia, she followed through on that objective.
No one, of course, can be certain that any chosen vice-presidential candidate will work out that way if destiny so dictates. But Kaine is a former mayor, governor and national party chairman, and he is currently a member of the Senate Foreign Relations and Armed Services committees. He has the broad and varied policy and political background to be a governing partner to Clinton if they are elected in November.
In Kaine, she has chosen a running mate who follows the pattern of the most effective and serviceable vice presidents over that last 40 years in both parties -- Democrats Walter Mondale, Al Gore and Joe Biden, and Republican Dick Cheney.
The senior George Bush might arguably also be included, if only because he was subsequently elected president for what was widely touted as a third Ronald Reagan term, although it hardly worked out that way.