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.”

Forty-three percent of respondents said they have never heard of Walker — the highest of any GOP candidate except Carson, with 54 percent. In addition, ten percent said they “can’t say” their opinion of Walker. (Bush’s never-heard-of number was eight percent, with ten percent “can’t say.”) Walker’s total was 27 percent favorable, 21 percent unfavorable, with a combined 53 percent never-heard-of or can’t-say…

For a candidate who starts out with little national recognition, a campaign is a long process of telling voters who he is. With the general public — and all three polls cited above were of the public, not just Republicans — Walker is still a mystery for a large number of people. Even some Republicans who know of Walker and like him base their opinion on what they know about Walker’s stand against public-sector unions in Wisconsin, and little beyond that. Despite all the attention the media has paid to the campaign so far, Walker is still starting out when it comes to explaining to voters who he is and why he’s running.