Wisely? NYT’s most relevant para:
Ultimately, Mrs. Clinton, who told PBS that she was “afflicted with the responsibility gene,” avoided taking a chance with a less experienced vice-presidential candidate and declined to push the historic nature of her candidacy by adding another woman or a minority to the ticket.
Kaine is Clinton’s Biden: an accomplished leader who stands on his own merit and is a reassuring, centrist choice for a majority of the country. Clinton’s goal, more clearly than ever, is to win.