Meh, if Trump wants to limit immigration from some countries, guess what, he can. If Congress doesn't like it they can get into a tussle over it, I predict they will just make political noise over it.
What is fucked up is that green card holders and people with visas are being denied entry. That seems like the government is working against itself. One branch okays them and another branch denies them. Trump is responsible for that mess, or rather Bannon is, he included green card holders and visa recipients against the advice of Homeland Security.
That is fucked up, people with jobs, families, lives are suffering major disruptions because why? They were already vetted and approved. The courts agree and they ordered customs to stop doing that. Now there is confusion within customs about what they are supposed to do.
Trump is failing at good governance.