Newt is his nemesis' indispensable ally:
Gingrich staying in the race does nothing but help Romney win toss-up states (for example, Illinois and Wisconsin). Gingrich has shown an inability to connect with voters outside the Deep South, but he has siphoned off enough voters to allow Romney to skim by with vote percentages of 41% or below in Michigan and Ohio. Where Gingrich is likely stronger (Arkansas, Kentucky and North Carolina, among other states), Romney's viability would extend to states he would have little chance in otherwise. With a plausible Gingrich campaign continuing, Romney would likely wrap up the nomination no later than early June, and probably by May, with a clear majority of delegates.