Re: policy being legal
Trump never cares if his executive orders are legal. In fact there is a strong advantage to them being illegal. It gives them better news coverage, he can point at the news coverage and say he owns the libs ("look at the crybaby snowflakes scream"), the order will not do any damage and he can say that the constitution is blocking him from making America great again. Get rid of the constitution so he can be the new permanent dictator and really get things done.
I was expecting Trump to cave in as soon as he realised his twitter account was at risk. Clearly he needs a new policy that appeals to voters terrified of immigrants. How about "Build a wall and make the Mexicans pay for it"?