Re: ...because we are a nation of laws
Indeed so. Enacting immigration law, like enacting all laws, is the job of the Congress, although in the case of immigration law it is one they have failed at pretty miserably for a good long time.
There is no genuine question that immigrants, on balance, have been bad for the country. It is fairly obvious (except, of course, fto those whose ancestors arrived from Asia 100 centuries or so earlier) that they have much improved the country since before it was one.
There is a basis, however, to argue that the US Presidency has got far to big for our collective good, and that, too, we may lay at the feet of Congress. President Obama's DAPA and DACA exercises are small compared to the five major several minor military actions since the end of WW II, not a single one declared a war by the Congress as required by Article I, Section VIII. It is time for it to end.
Obama, lauded though he was for it, did the unauthorized immigrants no favor by compiling the DAPA and DACA lists of those now possibly subject to deportation based on the current president's recission of his overweening executive orders. His only excuse may be that, like nearly everyone else, he though Hillary was a shoo-in.