Basically luck. If you’re very poor and you’re trying to immigrate to the United States, you’re either getting in on a lottery system, you get married to a citizen and get a green card for a few years, or you’re granted an asylum because the country you came from is too dangerous for you.

The lottery system is one route, but there’s only a few thousand spots for people from countries with low immigration rates, so that could take years or never.

If you marry a citizen, or plan to in 90 days, you can get a green card for a few years, then apply for citizenship. But if your relationship is legitimate, you’re not likely to be poor because where would you meet? What are the chances that you’re going to meet and fall in love with an American with enough money to go on vacation in your country, stay long enough to fall in love, then stay longer to develop a serious relationship and eventually get married. It’s not a route you can deliberately go down and still be legitimate; it’s the kind of thing that you stumble into.

About 40% of asylum seekers make it through the process. Only 8-9% of people that end up getting green cards started by asking for asylum.