Brain Game: Bill & Ted & Cal & Gerry & Jim's Excellent Adventure

Admittedly, today's Brain Game may prove difficult. If you don't know the answer offhand (I wouldn't have), a bit of research may make it clear. And this is just the type of trivia that seems destined to crop up on a game show someday. Good luck!

What do the names of these five presidents
- but no others - have in common?

William McKinley, Theodore Roosevelt, Calvin Coolidge, Gerald Ford, Jimmy Carter.