On Friday, Rick Santorum got a boost when he received an endorsement of Ohio Attorney General Mike DeWine. Santorum’s former Senate colleague had previously endorsed Mitt Romney.

DeWine stated, “To be elected President, you have to do more than tear down your opponents. You have to give the American people a reason to vote for you, a reason to hope, a reason to believe that under your leadership, America will be better. Rick Santorum has done that. Sadly, Governor Romney has not.”

The Romney campaign, of course, downplays the significance of this defection. Former New Hampshire Governor and former Bush 41 Chief of Staff John Sununu said, “Nothing has changed. Attorney generals don’t have much of an organization.”

Well, the Romney campaign didn’t seem to mind DeWine’s organizational strength when he was in their corner. Now it is entirely possible DeWine’s shift may prove to be the exception to the rule. But it illustrates Romney’s vulnerability and it does so in a bellweather state. Romney might have a bigger boat than Santorum. But what does size matter if it cannot stay afloat?

If Mike DeWine has jumped Romney’s ship what makes anyone think Donald Trump will stay on board?