Every non-Trump candidate in the Republican presidential race is having difficulties, but among the top three Ted Cruz is having a particularly rough go of it these days.

Senator Cruz fired his chief spokesman for spreading a misleading video of his Republican opponent in the presidential race, Marco Rubio. This comes after the Cruz campaign was accused by Dr. Ben Carson of spreading false rumors during the Iowa caucuses claiming the retired neurosurgeon was suspending his bid. Senator Cruz has had to apologize for both incidents, but it is creating a powerfully negative narrative: His campaign is one characterized by dirty tricks.

But what is far worse for Mr. Cruz are his third place finishes in South Carolina and Nevada. It’s not just that the Texas senator finished behind Donald Trump and Marco Rubio in both states; it’s that Trump won a plurality of self-described evangelical and born-again Christians, who were supposed to form the core of Cruz’s support. In South Carolina, Trump won a third of evangelical voters while Cruz won 27 percent and Rubio 22 percent. (Among non-college educated evangelicals in South Carolina, Trump crushed Cruz, while among college-educated evangelicals, Rubio beat Cruz.) In the Nevada caucus, things were worse. Among evangelicals, Trump won more than four in 10 evangelicals and finished 15 points ahead of Cruz. This comes only three weeks after the Iowa caucus, when Cruz beat every other candidate among evangelical voters.

Compounding Cruz’s problem is that he has very little support among non-evangelical voters. In Iowa and Nevada, he won 18 percent; in New Hampshire, just eight percent; and in South Carolina, only 13 percent.

What this means, then, is (a) Cruz is losing to Trump with voters he was hoping would form his base of support; (b) Cruz has very limited appeal to non-evangelical voters, much like we saw with Mike Huckabee in 2008 and Rick Santorum in 2012; and (c) the presidential race, after March 1, will move to states where evangelical voters are not nearly as dominant as they are in some of the early states like Iowa and the South.

There are other signs of Cruz’s limited appeal. As Ron Brownstein wrote:

Viewed through the ideological lens, Cruz’ support is just as narrow: Although [in South Carolina] he carried a 35-percent plurality of voters who identified as very conservative, he attracted just 17 percent of somewhat conservative voters and 7 percent of moderates. In Iowa and New Hampshire, Cruz also won at least twice as much support from “very” as “somewhat” conservative voters; his support among moderates has not cracked double-digits in any of the three states.

In Nevada yesterday, Cruz lost to Trump by four points among those who identified themselves as “very conservative” (38 percent v. 34 percent), while Cruz won only 16 percent of those who identify themselves as “somewhat conservative” and 7 percent as “moderate.”

Mr. Cruz might do well in the March 1 primaries, including in his home state of Texas. But after that, presumably, the terrain becomes less favorable for him. Which means if he hopes to win the Republican nomination he has to widen his support significantly, and soon. But right now, rather than expansion, he’s experiencing contraction. This is not where he wanted to be. But then again, that is true of everyone not named Trump.