Cruz is a fighter for our constitution like none other in politics today. You can verify this by the attacks from Rats and RINOs.
There are a lot of moving parts in this argument:
Coulter walked away from Christie months ago, specifically over the immigration issue.
Coulter attacked Cruz because of his past immigration policy, but she does not seem to realize that Cruz has become much more hawkish in recent months.
Romney had the most hawkish immigration policy from about 2006 to 2013.
However, Coulter does not seem to realize that Romney has backed away from some of his old immigration policies in recent months.
In my opinion, the GOP does not have one national candidate who can be completely trusted on Amnesty and Immigration.