This is kind of a timely activity for 2019. At some point it will expire and I'll remove it, but for now, it can be an interesting current event topic to talk about.
If you're not familiar with Naomi Osaka, she's a tennis player who shot to worldwide stardom in 2018. Her father is from Haiti and her mother is from Japan. Since Japan doesn't allow dual citizenship for adults, she'll have to choose whether she wants to become a Japanese citizen or an American citizen by her 22nd birthday in October 2019. I ask the students which citizenship they think she should choose. I tell them that she lived in Japan until was 3, but after that, she grew up in the US. She can speak and understand some Japanese but conducts her interviews in English. Her family feels like Japan gave her the chance to compete at the international level in tennis and has supported her a lot.
At the Junior High level, I just ask the students which citizenship they think she should choose, write a reason or two, and have them ask their friends what they thought.
For my general conversation class, I first pass out the article and summarize it. If you want to use more time you can have the students read it and check their understanding. I ask the students to think of the advantages of her being either a Japanese citizen or American citizen, and then ask them what they think she should choose. In my class I have the students discuss their ideas in small groups before doing a class discussion, but of course you're welcome to structure it in a way that works with your class. I'd say that reasonably advanced high school students should be able to read the article and discuss the issue, especially if it's part of an English elective class or club.
Some students take the politest possible viewpoint and say "She should make the decision by herself!" In that case, I say to the student that they're just giving their advice and it doesn't need to be a binding decision. I think I heard from one of my students that she said she's going to take Japanese citizenship, but I haven't checked up on that. As I said, this activity may not be relevant for much longer, so I'd recommend using it soon if it seems interesting!