The Primary Is Over, But When Will Mitt's Opponents Accept That?

The longer it takes for Rick and Newt to come around, the harder it will be to rally their fans in the Fall.

Scott Olson / Getty Images

Romney greet supporters at his Illinois victory party.

SCHAUMBURG, Ill. — Mitt Romney's Illinois blowout may have marked the end of the Republican nomination race, but his opponents have vowed to fight another day — a fact that could haunt him come November.

At this point, Rick Santorum and Newt Gingrich no longer pose a realistic threat to Romney's delegate lead. By the Associated Press's count, the frontrunner only needs to secure about 45 percent of the remaning delegates to clinch the nomination: Santorum would need over 70 percent.

But the stubborn insistence by Santorum and Gingrich to stay in the race regardless of the math — with both hanging hopes of an upset on the unlikely prospect of a brokered Republican convention — could start to have general election consequences for Romney. A significant portion of the GOP base that has spent months viewing Romney as a political villain: a RINO, a flip-flopper, a "Massachusetts moderate," or any other number of terms his rivals have used to attack him.

The longer Santorum stays in the race hurling those attacks, the harder it will be for his most active supporters to eventually direct their enthusiasm toward electing Romney when reality sets in. A core of true believers in Santorum's candidacy are becoming more invested in with each passing day, setting them up for a greater letdown when he drops out.

Of course, Republicans are quick to point to Barack Obama's success after a long, nasty primary fight with Hillary Clinton as evidence that Romney will do just fine in the fall. But in a party whose base is characterized by its demand for ideological purity, Romney — whose core weakness is an apparent lack of any ideology at all — will face a tougher time winning over Republican detractors than Obama did in coalescing the Clintonites.

The Illinois primary made Romney's "inevitability" stronger than ever for pundits and political analysts — but he has yet to convince his opponents. The longer it takes for them to come around, the harder it will be for Romney to rally their fans in the general election.

With Zeke Miller in SchAumburg and McKay Coppins in New York.