South Carolina seemed a natural target for Cruz after he rode a wave of evangelical support past Trump to win the Iowa caucuses two weeks ago. The voters in South Carolina were exactly the type that Cruz has courted; preliminary exit polling showed 72 percent of voters there were evangelical. Compare that with Iowa, where 64 percent of caucusgoers were evangelical, and you might expect Cruz to win South Carolina handily.

Yet, in contrast to Iowa, where Cruz outpaced Trump by double digits among evangelicals — 34 percent to 22 percent — Trump got more of the evangelical vote than Cruz in South Carolina: 33-27. Cruz’s shared of the evangelical vote only modestly outpaced Rubio (22 percent), who edged out Cruz for second place overall.

There’s only so much to go around, and if Trump continues taking a third of it and Rubio is competing too, Cruz’s entire path to victory becomes much more tenuous than it previously seemed.