This, from Silver’s Super Tuesday preview, is what I mean when I say that (implausible as it seems in the abstract) that Mittens has been inevitable since Perry imploded:
In Ohio, most of the delegates (48) are awarded winner-take-all by Congressional district. Note, however, that Rick Santorum does not have not have full delegate slates in some districts and will not be eligible to win them there.
Whether or not Mr. Romney is a favorite to win the popular vote in Ohio, however, he is probably the favorite to take the plurality of delegates there because of Mr. Santorum’s delegate problems.
And, as most people know, the ineptitude of the Santorum and Gingrich campaigns means that Romney can get almost all of Virginia’s 46 delegates uncontested. The spend-lotsa-cash-grind-out-the-delegates approach Romney has adopted out of necessity would have real vulnerabilities against a serious campaign, but Santorum doesn’t have the resources to run one and it’s not clear that Newt would have bothered to run a serious campaign even if he had the money he doesn’t have. When you eliminate the impossible, you’re left with Romney.