The problem is that marketable skill means Indians, Pakis, Filipinos, etc. coming here to displace U.S. workers by getting paid 1/3 the salary for the same job done by the U.S. citizen they replace. They're willing to live multiple families to a house (ghetto builders) to cut costs so they can afford the pay cut (that's a raise by what they'd make in their home countries). And they vote Democrat.
Cruz essentially screws the American skilled worker by advocating radical expansion of the H1-B visa program rather than reduction or temporary suspension to protect American workers. Since Trump entered the arena, Cruz has been silent on the visa issue. However, I still haven't heard him take a stance contrary to the one where he wanted a 500% increase in the number of such visas.