The feds will take action when another US city is attacked with massive loss of life. Even then, they'll move heaven and earth to prove the 'terrorists' (note use of PC generic term), were homegrown far right wing nuts. What we have is the frog in cold water. Keep turning up the heat, allow more and more in, in fact offer them free medical care, education and who knows what all, and soon the admin. and MSM say, gee, impossible to send 20 million back, we'd better make the best of it. Free movement and free trade in the hemisphere. Live and work where you please. Modeled on the Eurovision experiment, now in the dumpster.
Whoever thought up this crackpot scheme didn't notice that the citizenry south of the border speak Spanish, are mostly poor, uneducated, and think Americans work too hard. The upshot is, of course, that most who come here by hook or by crook never leave. Meanwhile, they're sending billions out of the country, propping up the corrupt Mexican oligarchy and they bring a Mexican or Costa Rican or whatever mindset and culture with them and in many cases, have no desire to 'assimilate'. Not to mention TB, Hepatitis B,C, whatever (many get jobs in fast food places), and leprosy, etc..
Newt Gingrich on Rush a week ago, had a sensible plan. Send them all back, allow them to apply for reentry with proper papers, promise of whatever job they had, thumbprint on green card so we can track them, and prompt deportation of those who break our laws. No shilly shallying. Professional, aggressive protection of our borders and sea coasts.
Plus, those who plan to stay should assimilate, learn English, apply for citizenship. Most don't have a clue as to the foundation of the US, the DOI, Bill of Rights, etc., the idea of individual liberty and the responsibilities that come with it.