Wisconsin Gov. Scott Walker is the leader in some national polls for the 2016 Republican presidential nomination. He’s also the least-known candidate in some surveys. There could be a relationship between those two factors.

Start with the new Fox News poll, done the last few days of March. Pollsters gave respondents, all registered voters, a list of seven Republican candidates — Rand Paul, Mike Huckabee, Jeb Bush, Marco Rubio, Ted Cruz, Walker and Ben Carson. “Please tell me whether you have a generally favorable or unfavorable opinion of each one,” the pollsters asked. And then they added, “If you’ve never heard of one, please just say so.”