Even if Cruz wins Iowa, and he should because Iowans like a preacher sounding politician, it’ll be his high water mark. Trump will destroy him in NH and SC and the rout will be on. Cruz is not leading in any state other than Iowa and he’s basically tied with Trump there. In NH Trump has a 20 pt lead over second place Kasich, not Cruz. He has a 15 pt lead in SC. A 19 pt lead in GA. Trump has a 19 pt lead in Florida. These are all Jan polls. Just found a poll other than Iowa showing Cruz in the lead. He leads Trump in Utah, 18% to 17%.
Momentum works, and you, nor I have any idea of the future.
It’s all speculation, but right now it looks like Cruz will win Iowa, then who knows.. probably Trump in NH (with Cruz 2nd in some form), then SC is too far away to tell what happens.