As next month’s GOP straw poll in Iowa draws ever closer, all Republicans who wish to be President are being urged to sign “The Marriage Vow: A Declaration of Dependence Upon Marriage & Family.” Michelle Bachmann and Rick Santorum have already signed. The Pledge is a bizarre combination of 1950s sexual conservatism and Cold War-style doomsday-ism (it opposes “infanticide” and the “enslavement” of military wives), which it blends into an obsession with marriage and morality. It claims, with an absolutely straight face, that “candidates’ positions on core values, such as marriage, correlate directly to their moral stances on energy issues,…