Ronald Reagan was backed by Congressional legislation that had passed both chambers and had been sent to his desk for signing.
Ronald Reagan was also blindsided and betrayed by the false promises of the pro illegal alien lobby.
Ted Cruz has the benefit of hindsight. Ted Cruz is also not concerned so much with illegal aliens as he is with subversion and corruption of the US Constitution.
Reagan came from a time in American history when one's honor was based in part on one's word of honor. There is no honor among progressives, because to them the end justified BAMN, and Cruz and the rest of us know that.