Earlier quoted context omitted.
The ahem _United_ Kingdom is already a _Union_ of 4 states - England, Wales, Scotland and Northern Ireland. I'm not saying no to joining the European Union or the American Union, but if it's the USA, no it would not be just 1 new state. And Northern Ireland may have other ideas of who to join.
We can add Ireland to the USA fold as well. That would solve the Northern Ireland Situation.
No, you can't. The Republic of Ireland is very much part of the European Union of States.