The national media have virtually proclaimed the Republican presidential race to be a two-man fight between Texas Gov. Rick Perry and former Massachusetts governor Mitt Romney. They point to national poll numbers, which are largely fed by huge media coverage and name identification, as evidence that Perry is now the front-runner and the rest of the field is kaput. Even Rep. Michele Bachmann (R-Minn.) is finding it hard to maintain the media spotlight and her standing in the polls.

But are all but the top two candidates in national polls irrelevant? And more important, could some of them make considerable trouble for front-runner Perry, who is managing to get by on hot rhetoric and, what one political adviser on another campaign calls, “broad political promises and platitudes”?

There are in effect two campaigns going on. One centers on national media, polls and big-dollar fundraising. But the other is on the ground in early primary states, in retail political events and in local media editorial board meetings. Perry and Romney are dominating in the first. But in the second others are making headway.

Bachmann is keeping up a steady pace of campaign appearances in Iowa and South Carolina. The Post reported that on Thursday she “may have hit the jackpot” with appearances at her town hall gathering by popular South Carolina Gov. Nikki Haley and Rep. Tim Scott (R-S.C.) , a Tea Party favorite. Plainly, she has a following there, particularly if either of these conservative rock stars formally endorses her.

Meanwhile, Rick Santorum, who came in a surprising fourth in this month’s straw poll in Ames, Iowa, with virtually no money, has been to South Carolina 20 times already. He spent two days there this past week. He held fundraisers, met with religious leaders and Tea Party activists, and had a series of private an public meetings with voters. He’s trying to make the case that he is the un-Obama.

In 2008 the country elected a candidate with high-flying rhetoric and few specific policy proposals. Santorum spokesman Hogan Gidley tells me, “We tried that experiment with Barack Obama, who had no real experience, and look where we are now.” He says that in early primary states there is a premium on face-to-face campaigning. “They realize there is a huge difference between leadership and showmanship . . . . They don’t want you to come; they expect you to come and answer tough questions.”

And that is where Santorum sees an opening and perceives weaknesses in his opponents. Perry has had a successful run as governor of Texas, but could he get through a tough interview with Fox News’s Chris Wallace, for example? Or the Des Moines Register’s editorial board? He’d have to tell voters what he thinks of Russian reset, what Supreme Court cases he thinks were wrongly decided, which parts of the Simpson-Bowles deficit reduction plan he agrees with, what sort of Medicare reform he favors and much, much more. There is no indication he has specifics on any of these issues.

And there is the rub. The knock on George W. Bush that he was an anti-intellectual and uninterested in policy turned out to be dead wrong. He was an avid history reader and championed (unsuccessfully in some cases) detailed policies on stem cell research, Medicare Part D, education, immigration reform, Social Security and tax reform. And he went outside the Pentagon bureaucracy to redesign the Iraq war policy and implement the surge. But what if Perry is in reality the equivalent of the George Bush caricature — all bluster, no substance?

If he is, that is the opening for Santorum and other candidates. Bachmann is beginning to highlight specific legislative accomplishments. A spokesman e-mails me, “She’s been an unwavering opponent of big-government liberalism and has stood firm on cutting spending, cutting taxes, and holding the line on life and traditional marriage. That’s why Heritage scores her in their Top 10 list of members of Congress who fight for freedom, opportunity and prosperity. The very first bill Rep. Bachmann authored in Congress (in her first month in office in 2007) was a meaningful health-care reform bill (that garnered 64 co-sponsors), and one of the bills she most recently authored would pave the way to dismantle Obamacare (95 co-sponsors).”

Likewise, Santorum is pounding home the message that, as the only former lawmaker in the race with a list of bipartisan policy achievements (e,g, welfare reform, the partial-birth abortion ban, Iran sanctions), he has a leg up on his opponents and is uniquely suited to face the challenges we ace. Gidley says, “The difference between Rick Santorum and the rest of the field is he can say, ‘This is what I would do. This is how I would do it. And this is what I’ve done before.’” That is perhaps why, despite his staunch conservative views, Santorum doesn’t going around hurling insults at Washington itself. Gidley says matter-of-factly, “At the end of the day you actually have to govern something. Washington is broken. We know that. But this is nothing new.” Can Santorum break through the media clutter to make the case that he’s the one to fight through the polarization and craft conservative solutions with some Democratic support?

Well, that is what the primary process is all about, namely being able to differentiate yourself from the rest of the field. The good news for a candidate such as Santorum is that early-state voters pride themselves on “kicking the tires” and running candidates through their paces. It’s generally not enough to step off the bus, throw out some generic lines (“Lower taxes!” “Reduce spending!”).

The debates offer both Bachmann and Santorum a prime opportunity to make their mark. Bachmann easily dispensed with Tim Pawlenty in the Iowa debate, raising his deviations from conservative views (e.g., cap-and-trade). She surely will look to do the same to the front-runners in the series of fall debates. Her spokesman declines to go into specifics, saying only: “What voters are looking for is a constitutional conservative who is consistent, and that’s what Michele offers.” No doubt she will raise Perry’s flip-flops on mandatory vaccination and gay marriage, while going after Romney on health care.

Santorum, perhaps more than any other candidate, can use the debates to advance his standing. He’s already shown himself to be a tough debater, challenging Bachmann on the debt ceiling and Rep. Ron Paul (R-Tex.) on Iran. It’s in the debates that he hopes to not only differentiate himself from the competition, but also to make the case that he is able to go head-to-head against Obama. Both money constraints and his own familiarity with the issues have eliminated the flock of policy gurus and consultants that accompany the other candidates, formulating, shaping, and adding “nuance” to their positions. In a debate, when candidates stand alone and are most vulnerable, Santorum may be better equipped to show up those who rely on the coterie of advisers to churn out platitudes tested on focus groups.

The challenge for a candidate such as Santorum is great. He has limited time and opportunities to break through. But his presence in the race and the case he is making (select an accomplished conservative who knows his way around D.C.) pose a challenge to the newest front-runner. For Bachmann, her ability to show some policy finesse and challenge the front-runners’ conservative bona fides will be key.

One national media magnet (Tim Pawlenty) has washed out, another is going nowhere (Jon Huntsman) and another is untested and lacking policy chops (Perry). In such a race, Santorum and a reinvigorated Bachmann could surprise, or at the very least, make the front-runner look a whole lot less impressive.