The Republican race is taking its toll on Romney

Rick Santorum’s surprise clean-sweep of three states on Tuesday certainly suggests that the battle for this year’s Republican nomination will go on a fair bit longer than looked likely after Mitt Romney’s win in Florida a week earlier. But it doesn’t change the fact that Romney will, most likely, emerge the winner. But where it once looked like he’d make a decent — if unexceptional — challenger to Obama in November, he’s starting to seem much less electable.

Just look at the slide in his poll numbers. At the beginning of the year, a Washington Post poll found that 39 per cent of Americans had a positive view of Romney, against 34 per cent with a negative one — a net positive rating of 5 points. But in their latest, less than one-in-three have a good opinion of him, while almost half have a bad one — his net rating has dropped to minus 18:

And his head-to-head polling with Obama tells a similar story.