Barack Obama may still be proposing policies that strike conservatives as weak and foolish. But after his aggressive response to President Bush's apparent criticisms of his foreign policies last week, it's clear that he's doing so in a forceful and politically savvy way. Obama's approach to foreign policy - which emphasizes negotiations more than threats of military action - first emerged as a campaign issue last summer, when Hillary Clinton was looking to show off her expertise and make Obama look like a neophyte. She tore into him for appearing to rule out a nuclear response against Pakistan, should it...