Jeb Bush and Hillary Clinton badly need each other. They cancel out each others' greatest weaknesses and deprive their foes of some of their strongest arguments.Both have similar flaws and are vulnerable to the same charges: that they are too old (Jeb would be 63 on election day 2016; Hillary, 69), too out of practice (Jeb was last elected governor of Florida in 2002; Hillary was last elected senator from New York in 2006), too tied to previous presidents (their close relatives have won five of the last seven presidential elections).Put it another way: If the choice is a Bush vs. a Clinton, one aging member of a family dynasty with ties to Big Money has to win. Neither nominee would have to worry about an insurgent opponent promising a fresh new face (like, say, a junior senator from Illinois).These musings are prompted by the rather coy announcement posted on Facebook that Bush "will actively explore the possibility of running for president" in 2016.