As Herman Cain rises in the polls, Beltway Republicans are wondering whether he is running a “serious” campaign, complete with bustling staffers, field organizers, and national money raisers. His recent bus tour around Tennessee and northern Virginia, hawking his latest hardcover, has only increased chatter about his efforts in early primary states, which appear lackadaisical.

But behind Cain’s bookstore stops, his political team is building — just not in usual frontrunner fashion. Instead of betting the campaign on Iowa, or another winter primary, his small team of advisers is attempting to play nationally, using Cain’s ubiquity, on the airwaves and the Internet, to boost his candidacy.

With 75 days until the Iowa caucuses, sustaining a top-tier candidacy with media attention, debate fireworks, and online donations is risky. But Cain’s operation is confident in its strategy. They say their deep experience in grassroots advocacy, often outside of party lines, will sustain the campaign.

Cain’s senior staff, to be sure, is more than a band of amateur enthusiasts. Most are veterans of Americans for Prosperity, an influential group with close ties to tea-party leaders and high-profile donors, such as Charles and David Koch. AFP, in many respects, launched Cain as a national conservative figure in 2005, when it tapped him as a spokesman — and he has benefited from the association.

As he traveled the country, championing AFP’s free-market principles, Cain developed relationships with strategists who lacked reputations in Washington but had extensive experience elsewhere, especially in Midwestern conservative circles. Mark Block, Cain’s campaign manager, was one such operative (and has been the brains behind Cain’s White House hopes). Another is Linda Hansen, Block’s deputy.

To top GOP consultants, the Cain-Block alliance has been astonishing to watch, not only because it has worked, but because of the differences between them. Cain, a charismatic African-American businessman, had eyed a presidential run for years but had few political prospects as a relatively unknown talk-radio host from Georgia with a failed Senate primary run under his belt.

Block, then directing AFP’s Wisconsin chapter, saw things differently. He told Cain last year that if they took an alternative route to the nomination — stoking buzz instead of buying it — they had a shot. Cain, in his mid-60s, a long business career finished, agreed. Sources inside the campaign say both men remain true believers in that mission.

Indeed, there is a bond there, sources say, more than employer-employee. Block, once a rising star, was looking for a professional comeback of sorts, a few years after he was fined for campaign violations in Wisconsin. Cain, for his part, was seeking to join the national conversation, not merely disappear into political history as the Man Who Once Challenged Bill Clinton. (Cain, then chief executive officer of Godfather’s Pizza, famously challenged Clinton during a health-care forum in 1994.)

But Cain’s crusade is about more than green rooms or final career laps. And his autumn rise, campaign insiders insist, has not been sudden, or a lucky side effect of Cain’s charisma. Sure, other candidates have risen and fallen, and the Georgian could easily do the same, but Cain confidants bet he can last, due to the way the campaign was built and continues to be run — with catchy policy proposals and guerrilla maneuvers.

All spring, for example, Block used AFP tactics to build Cain’s campaign, emphasizing name-identification and messaging first, and running field operations on a shoestring budget. By late May, days after Cain officially joined the race, the work paid off. Using social media, outreach to conservative media, and appearances at tea-party rallies, Cain began to gain. Gallup’s May survey of GOP voters showed him with the highest “positive intensity score” in the field.

Cain’s poll numbers have fluctuated since, but his campaign has doggedly stuck to its original strategy, shrugging off its thin staffing as it works to keep Cain visible. J. D. Gordon, the campaign’s spokesman, says that the campaign will not shift its main focus to Des Moines or Manchester. But do look for Cain to make more early-state stops, now that he’s attracting more nationwide support — and has wrapped up the book tour. “We already have field staff in twelve states,” Gordon says. “And we’re launching in more states soon. We’re looking to spend more time in Iowa and New Hampshire.”