The Texas senator is expected to win the state on Tuesday night, having a substantial lead in almost all the polls, aside from a notable outlier. As Nate Cohn persuasively argued in The New York Times, Cruz’s advantage is deeply entrenched in the demographics of Wisconsin: It’s a state where the Republican population skews towards groups that are generally less-inclined to vote for Donald Trump (the college-educated; Protestants active in church life; whites of north European ancestry).
Cruz better earn his expected wins, because the stakes couldn’t be higher for him. If Trump pulls off an upset victory in Wisconsin, then it’s game over for Cruz—there is no plausible path to stop Trump from getting a majority of delegates.
Conversely, a Cruz win would damage Trump, but not fatally. It would open up the possibility that Trump will fall short of the 1237 delegates needed to secure a clear victory. But more than that, Cruz can use the victory to craft a narrative that he has momentum, improving his stance in the remaining states. A Wisconsin victory would also strengthen the case Cruz will have to make, if there is a contested convention, as to why he deserves the nomination even if he has less delegates than Trump.