If there was any remaining doubt about who the Republican nominee for president will be this November, last night’s Wisconsin primary results should have ended it. Previously, Rick Santorum had tested Mitt Romney in the key Midwestern battleground states of Michigan and Ohio. In both states, Romney narrowly prevailed, but Santorum beat him within some of the Republican coalition’s key demographics: conservatives, those making less than $50,000 and those who did not attend college.

In Wisconsin on Tuesday, however, Romney put a stop to that. Not only did he win among all voters by a safe five-point margin, he also beat Santorum among all of the groups listed above. And Santorum had campaigned hard in Wisconsin. In the other two Tuesday contests where Santorum did not campaign, Maryland and the District of Columbia, Romney cruised to easy victory. All told, Romney captured at least 83 delegates Tuesday to Santorum’s six.