Jonah Goldberg‘s latest column posted at National Review Online asks whether Wisconsin Gov. Scott Walker is ready for the spotlight that awaits all serious presidential candidates.

Walker’s defenders, and they are legion, will tell you that he never planned on being a top-tier candidate this soon. It’s a sign of his broad appeal, the grassroots hostility to a Jeb Bush coronation, and the liberal media’s fear of Walker’s potential that he’s being put under the microscope so early.

Walker said as much to York, “We had no idea that after that Iowa summit there would be that kind of acceleration to the race. But we’re here, and we’re not going to complain about it.”

All of that is undoubtedly true to one extent or another, and Walker’s reply is a good one. But so what? He’s still facing the challenge of being the front-runner before he is ready.

It’s a bigger problem than it might seem. Walker planned on defining himself to the country on his timetable. With that plan in ashes, he’s facing a liberal news corps and a Republican field of competitors hell-bent on defining Walker if he won’t. From the media, that means lots of questions about President Obama’s religion, Walker’s views on evolution, and other ridiculous gaffe hunts.

Walker has been “punting” — his word — on such questions, but also on more serious topics. That is a fine tactic when few are paying attention. Other candidates have been punting on various issues too, but no one knows or cares because they aren’t the front-runner. When you’re in the spotlight, punting stops being a way to avoid giving an answer and instead it becomes the answer.

Walker is in danger of being the guy known for not having a good — or any — answer to tough questions. That’s particularly poisonous for him, given that he is running on leadership and truth-telling.

Of course, it’s not all downside. Being unfairly targeted by the media also has the effect of boosting your name and, more important, causing the rank and file to rally to your defense. For example, New York Times columnist Gail Collins attacked Walker for higher-education cuts that occurred before Walker took office. And the hard Left is frequently concocting attacks they then have to retract. But Walker cannot afford to become merely a culture-war avatar of grassroots resentment against the “lamestream media.”

That’s the route to a radio show, not the White House.