Just want to concur with Sweeting, as an Englishman married to an American, and having been through the immigration process.
Plenty of trips to the US embassy in London on that side, interview, paperwork, fees… it was a robust thing. I got a green card, which lasts for ten years, but the expectation is you will turn it into citizenship when you get here. I didn’t do that, but somewhere along the way, about 7 years in, I turned it to citizenship as Trump was on the rise, and I didn’t like the way he was talking, and didn’t want to be vulnerable to some whim of his that would separate me from my wife and kids.
One ridiculous aspect of the citizenship test they had me do was to demonstrate some competence in the English language. I sat in an interview with a government official, and they read a simple sentence and I had to write it down. I explained that English is my first language, and had been speaking and writing it my whole life, including through University and Master’s, but they had no humor or facility to understand the situation in front of them.
So I wrote out something about a cat sitting on a mat, or some such thing, and did my bit to preserve the Union 
There was a civics test and you had to know 100 questions about politics and American history and so on. I randomly ask colleagues some of these questions - people who have been here their whole life and graduated college - and they don’t always pass with flying colors.
The citizenship ceremony was a meaningful experience, I would guess about 40-50 of us, and many nationalities from all around the world represented. The judge did an impassioned speech about making your way and adding to the fabric of the country, American dream sort of thing, and I distinctly remember her saying that in America nobody is above the law. Er, I don’t know about that one! Have you seen what’s been happening?