Lots Of Pluralities
So far, 16 Republican states have fully reported results (including Kansas tonight) and in none of them has a candidate won a majority of the vote. The nearest misses were in Massachusetts, where Trump got 49 percent of the vote, and in Kansas, where Cruz got 48 percent.
We’ve got too much going on tonight to confirm whether this is a record of some sort, but it looks as though it might be. In the contentious 1972 Democratic primary, for example, Ed Muskie got 62 percent of the vote in Illinois, the fourth state to vote. In the 2012 Republican race, Mitt Romney got (just barely) over 50 percent in Nevada, the fifth state to vote.
Note, however, that Trump could plausibly get to 50 percent in Louisiana, where polls close in a few minutes. He was as high as 48 percent in one poll of the state.
