Your problem is you don't understand a change in policy from declaring a national emergency.
I understand them just fine. One of them (declaring a national emergency) is within the lawful reach of Presidential powers. The other (changing policy) is not.
Comparing DACA to Trump's detainment policy would be more appropriate.
....No, that was a decision within the law, and following the law. A more direct example might be if - for instance - if Trump were to decide that the Corporate Income Tax Rate should be 5%, but, with a Democrat-controlled House refusing to act, ordered the IRS to just assume that the tax law
had be rewritten to reduce the Corporate Tax Rate to 5%, effectively re-writing the law, but without Congressional approval.
Also, nice break down about what everybody else might think or say, but we are actually interested in your opinion about deciding what is and isn't dangerous.
Power is dangerous, and precedent defines much of the boundaries within which power is exercised. We do not remember
Marbury v Madison, for example, because whether or not William Marbury received a judgeship was so critical, but because it set the precedent that
the Supreme Court could overturn acts of Congress and decisions by the President. The SCOTUS has since then applied Judicial Review in ways
far beyond it's initial usage of refusing to act as an enforcer.
The
Precedent that Trump is setting here is that
the President, having been granted the right to determine what is and is not a National Emergency by Congress, has the right to do so, even when members of that Congress may not agree with his decision. It's dangerous because
what Congress did was dangerous, but it is still limiting - Trump has only the authorities granted to him by Congress in this case, along with the (too few, agreeably) restrictions tied to it. The act of building a wall in and of itself isn't dangerous, it's the Executive Power that is.
The
Precedent that
Obama set, however, was not that the President can exercise authority duly granted him by law in order to achieve a policy preference - it was that
the President can take legislative power from the Congress without their permission by effectively rewriting the law however he pleases. This means that the President is no longer limited by the authority granted to him by the Constitution, but is limited only by the authority granted to both the President
and the Legislature under the Constitution. It is a
vast power grab, under the act of doing something more restrained, just as
Marbury v Madison set the SCOTUS over our other branches in authority, under the act of doing something more restrained. The act of not deporting illegal immigrants who came here as children in and of itself isn't dangerous, it's the radical expansion of Executive Power that is.
A future Democrat President can take Trumps precedent and (as Pelosi has warned) declare climate change to be an "emergency", allowing him (or her) to accomplish parts of the Green New Deal, so long as it does not violate individual or state rights, within the limits put on him (or her) by Congress. A future Republican (or Democrat) President can take
Obama's Precedent and do
whatever they want, without any Congressional limits at all. That is a different (and more dangerous) thing indeed.
That's one, number two is to stop equating DACA with a fake national emergency.
I am not saying they are equal. I am saying that the power grab inherent in DACA is more dangerous than the power grab inherent in the President using a definition of Emergency that Congress would not agree with, because the first is an unrestrained vision of executive power, and the second is not.