Fred Barnes, writing in the Wall Street Journal:
"With Rick Santorum's exit, Mitt Romney's path to the Republican presidential nomination is clear. But his road to the White House is hazy. To defeat President Obama and capture the presidency, Mr. Romney will have to make significant changes in his campaign.
"He's already improved his campaign in important ways. For a Republican, the usual strategy has been to run as a conservative in the primaries, then move toward the center in the general election. Mr. Romney has done the opposite, starting in the center before gradually latching on to conservative positions on taxes, spending, entitlements, social issues and foreign policy.
"He's better off for having become specific. Sticking to generalities, as he once did, made him look evasive and shifty. And Mr. Romney no longer relies on his business background as his chief talking point. His résumé alone wasn't enough to qualify him for the presidency.
"Now there's no turning back. He's embraced the election as a stark choice between right (him) and left (Barack Obama)."
Whole thing here.