

Supreme Courts around the world have found all sorts of ways of exercising power. They can deputize citizen volunteers to serve as temporary court enforcers. They can outright order the military to stand down and arrest the president. Hell, they could dig into the ancient tradition and declare the president an outlaw - literally outside the protection of the law, making it legal for anyone to straight-up kill the guy.
MAGA will decide they want to deport Irish-Americans. Ireland will respond by saying they don’t let people claim residency that many generations back. MAGA will piss and moan. Eventually they will make a deal with the UK government. The UK government will build a large prison camp in Northern Ireland, right near the border with the Republic of Ireland. Irish Americans will be banished to the camp, in direct line of site from ROI land, until such time as ROI willingly accepts them in as refugees.