There were reliable sources warning before the border deal, but conservative talk radio IGNORED them

Investors Business Daily has a sensible editorial on birthright citizenship

Birthright Citizenship: It's About The Law, Not Mob Rule:

As Daniel Horowitz recently noted, the only legal justification for granting citizenship to illegals comes in a footnote to the Supreme Court's Plylor V. Doe decision. In it, ultra-liberal Justice William Brennan claimed that illegal aliens had a right to claim jurisdiction under U.S. law. But it's never really been decided as a separate issue by the Supreme Court.

So on strictly constructed constitutional grounds, Trump is right. Whether you hate him or not.

Of course, the counter-argument to that is: We have allowed this system to go on for so long without direct challenge it now has the force of law. That is a legitimate legal argument. It deserves serious consideration, either by Congress or the courts.

And that's our point. As bad as we think birthright citizenship for illegal immigrants is, any decision should be a matter of law and democratic process, not of screaming and name-calling. We have a Congress. We have a court system. The president has, in effect, challenged them to do their job. So they should do it.

If they don't, then Donald Trump, as the nation's chief executive, is well within his rights to issue an executive order if he thinks birthright citizenship represents a violation of the Constitution and threatens harm to the nation. It's his duty.

He has precedent. Axios.com quoted Trump telling reporters Wednesday that, if President Obama can "do DACA, we can do this by executive order."