If John Bolton runs for president — and he very well might — he will run to win.

“I would not run as a one-issue candidate,” Bolton says as we chat in his corner office, high above downtown Washington at the American Enterprise Institute. “Anybody who does that is declaring himself to be marginal.”

Bolton, a former ambassador to the United Nations, is no sideshow. His walls are dotted with presidential appointments: He served Ronald Reagan as an assistant attorney general. George H. W. Bush tapped him for a top post at the State Department. For Bush the younger, he returned to Foggy Bottom, overseeing arms control.

But it was in New York City, at that glassy rectangle towering over the East River, where Bolton left a bruising, indelible mark. As George W. Bush’s U.N. ambassador, he gleefully tangled with fussy Europeans, Third World despots, and international bureaucrats. That experience, he reckons, is more than enough to make GOP primary voters, at the very least, curious.

It is also why, even in mid-June, Bolton continues to make calls to close friends, pollsters, and political consultants, mulling his options. “Clearly the field is not fixed,” he says. “I do not sense any coalescing around a particular candidate. The ups and downs in the polls are an indication of how volatile things are, and how people want to find the right person to beat Obama.”

Could that person be a 62-year-old ex-diplomat with a snowdrift mustache? Bolton thinks it’s possible. As he sees it, 2012 will be an unusual year, the first in his lifetime where someone with his résumé could leap into contention. “Nobody is settling,” he says. “The momentum keeps shifting on the right. That’s why other people are thinking about getting in — and why even a relatively late start, in historical terms, by a nonpolitical figure, is not disqualifying.”

Watching the recent CNN debate, Bolton was unimpressed. “Bumper-sticker responses to bumper-sticker-length questions,” he says. “Are we going to have a debate about the Republican debate, or is the media going to have that debate? It’s that sort of thing that actually impels me to get in, just to stand up. I hope I would have had the courage in that debate, if I was asked the deep-dish-pizza question, to say that this is silly.”

Bolton pauses then rubs his chin. It all sounds good — almost too easy: fiery conservative enters the race, shakes up the field, and things snowball. In many respects, Bolton would love to join the presidential fray tomorrow, if it meant simply showing up. But he wonders whether he is ready to build a national political machine. “I am tanned, rested, and ready to govern,” he smiles. Mounting a slick, savvy campaign, well, that could be difficult.

His reluctance is more practical than personal. Bolton, more than he lets on, is a political junkie. In 1964, growing up in working-class Baltimore, he skipped school to campaign for Barry Goldwater. In almost every sense, the nitty-gritty of campaign life appeals to him. Rather, it is that looming climb up the fundraising mountain, where so many have been lost, that makes him cautious. “The overall effort requires very pronounced skills, and I have to decide whether I am prepared to go through with that,” he says. “But the other things, the handshaking at the plant gate at eight in the morning? I would enjoy that.”

He will decide by Labor Day, a self-imposed deadline. Until then, Bolton is drafting a multifaceted strategy, one that would enable him to enter late. He recognizes that his tenure at the U.N., or perhaps his appearances on Fox News, may be how many know him. If he runs, he would need to show voters that he is more than that smart guy on cable television, more than an elder statesman.

To the viability question, Bolton says, game on. “I would focus first on New Hampshire, followed by South Carolina, Florida, and Nevada,” he says. “I think that is a very understandable path to the nomination.” Iowa, however, is probably out of the equation. He is against ethanol subsidies, for one, and it may be a bit too late to build a base there, “where the 99 counties are like the 99 names of God.”

Still, even as the clock ticks, Bolton firmly believes that competency and leadership will be a major factor in the primary. And it is on this front, he says, where he could swoop in, make his case, and surprise.