I think it's a much better discussion to weigh the merits of restricting immigration (Trump's "extreme vetting") rather than discuss whether the order is legal or not.
Not surprisingly, I believe that our number one responsibility is protecting Americans on our soil, in every way possible above those who would visit or desire to live here. That means jobs first, including training for skilled labor positions and giving Americans the opportunity to do the jobs "that nobody wants" (incredibly insulting to those unemployed). It also means making our country safe from those who would come here to do harm.
Our history is tainted with armchair quarterbacking after the fact. People continually speak about what a mistake Japanese interment camps, but also disregard the fact that the reason our planes were out of hangars and iin plain view to be attacked by air at Pearl Harbor is that there were credible fears that Japanese loyalists living in Hawaii may sabotage them in the relative secrecy of hangars. People never mention this but Italian Americans born in Italy were not allowed within X miles of the coastline while Italy was part of Axis powers - even the great Joe DiMaggio's parents could not operate the family restaurant near the wharf in San Francisco.
You can debate the merits and humiliation of these programs, but the fact is that you CAN debate them. that we were at war and American leadership must protect its citizenry. Perhaps neither ethnic group did not pose a credible threat, perhaps they did, but the reality is that espionage did exist within our borders and the government was acting in the perceived best interest of Americans as a whole.
I do not buy for even a millisecond the notion that restricting travel until we can ascertain that an individual poses no threat to Americans is somehow radicalizing extremist Muslims. I do think by perpetuating this false notion actually riles up the crazies, much like the liberal funded BLM movement, which had a direct correlation to cops being slaughtered while on patrol by crazy, angry individuals.
By and large Americans want what many Muslims want who are living in countries in the Middle East - peace, prosperity, and the threat of radical groups like Al Qaeda, ISIS, and the Taliban destroyed or dismantled. Restricting travel until a reasonable background check can be conducted helps keep our country safe from outside terrorists. It's not perfect - nothing is. But we must do everything within our control to stop those who would do harm here and abroad by planning and executing carnage on innocent victims.