Paul A. Rahe writes at Richochet.com:

Governor Romney’s choice of Paul Ryan as his running mate suggests, in fact, that my suspicions were correct. For by making this choice, Mitt Romney is declaring war. There will be no evasion, no triangulation, no attempt to mask what is at stake in this election. Instead, Romney and Ryan will directly confront Barack Obama and call him to account for putting us on a ruinous course.

This will alter radically the dynamics of the race. The money spent by Obama trying to demonize Governor Romney will prove to be money entirely wasted. The election is not going to be about Mitt Romney. It is not going to be about the sexual revolution. It is not going to be about Bain Capital. It is going to be about the failed policies of Barack Obama, about their dangerous character, and about the sober, sound alternative the Republicans represent.

h/t Doug Ross