Mercer Island isn’t in Seattle. I’ve posted a lot on Paul Robeson and have cited my sources. Can’t dig up my cites at the moment.
That's splitting hairs, isn,t it? It's a tiny island separated from downtown Seattle by a bridge, and it's considered part of the Seattle metro area.
If Robeson had taught there, it would certainly have been remembered, and celebrated, by Seattle historians. According to his bio, he underwent major protrate surgery in 1955, and became increasingly mentally disturbed. When his passport was restored by a Supreme Court ruling, he gave concerts in the both the Soviet Union and Carnegie Hall in 1958, then moved to England sometime before 1960. There's no evidence of, or rationale for, his teaching at Mercer High School during the years Ann Dunham attended.
Talk about splitting hairs. It's a suburb about 10 minutes from downtown, less than five minutes from the city limits. I know because I live in Seattle and go there all the time.
It sits on an Island in Lake Washington, whose western shores mark the Seattle city limits. You just go west from Mercer Island accross the I-90 floating bridge and you're in Seattle.
It's a very long trail that runs from DuBois, Robeson, Malcolm X, Frank Marshall Davis to Chicago and into the White House.