The savagery of South Carolina politics is now so ensconced in the imaginations of American political journalists and commentators that any report on the state’s presidential primary is almost obliged to include one of two things, and usually both: (1) a reference to Lee Atwater, the famously unscrupulous Republican strategist and South Carolina native, and (2) the brutal 2000 contest between George W. Bush and John McCain, in which someone (no one’s sure who) spread false rumors about McCain having a mixed-race love child.

But is South Carolina’s primary really as bad as that? Well, no. Or rather, yes. Sort of.

Presidential primaries aside, South Carolina political campaigns are (I suspect anyway) no nastier than those of other states. And in any case, much of the nastiness is only apparent in retrospect. I’ve lived in South Carolina for most of my life and was here for the legendary showdown between McCain and Bush in 2000, but I have never met anyone who received one of the notorious “robo-calls” or fliers making outrageous claims about McCain.

That’s not to say such things never happened — only that it's likely a very small number of people experienced them at the time.

Nor is it clear to me that such preposterous tactics actually change anyone’s mind. The story about the whisper campaign alleging that McCain had an illegitimate black daughter, though it may well sound to a non-Southerner like the sort of thing that could flip an election in the South, would have been regarded as obviously mendacious to the average primary voter. Indeed, the most vicious of these shenanigans seem calculated to generate sympathy for their ostensible targets and repugnance for their ostensible beneficiaries.

None of this, of course, means these shenanigans don’t take place in South Carolina. They do. And there are essentially two reasons for it.

The first is not very interesting but nonetheless true. South Carolina is generally the third nominating contest (thought it's fourth for Democrats this year). By the time candidates leave New Hampshire and head south, as The Post’s Ben Terris recently pointed out, “the window to win the nomination is rapidly closing, and there’s little advantage in holding back.” Campaigns that aren’t dominating the contest become desperate by this stage in the primary season.

The other reason for the Palmetto State’s dirty-trickery has to do with the political culture in which it takes place. A little background:

South Carolina’s legislature dominates its politics. The governor has a high profile and easy access to the news media, as any governor would, but the office comes with very little real power. The most important state agencies — transportation and education, for example — are not run by the governor at all but by boards appointed by legislative leaders. Even the judiciary is unilaterally chosen by the General Assembly.

Partly as a result of the legislature’s hegemony over the other branches, the body is largely non-ideological. Members disagree about many things, but those things only rarely involve fundamental differences of principle. To catch a sense of just how collegial and consensual the South Carolina legislature is, consider: In 2013, the Republican speaker of the House, Bobby Harrell, became the subject of a state grand jury investigation of a variety of offenses, including misuse of campaign funds and misconduct in office. During the entire year of the grand jury investigation, not a single Democrat in the House or Senate raised even the mildest criticism of Harrell or suggested that he should step down. (He was indicted and convicted in the fall of 2014 and forced to resign.) It’s hard to imagine this happening in any other state.

The way to get anything done in this kind of consensual and clubby political culture, therefore, is to cultivate relationships with state lawmakers. Ideologically motivated grass-roots activism has almost never made much headway in Columbia. With the rise of the tea party in 2009, that has begun to change, but it’s still routinely and correctly observed that South Carolina politics are “relational” rather than “confrontational”; what matters is who you know, not what pressure you can bring.

All this has direct bearing on the state’s presidential primary. South Carolina’s political consultants do not typically engage in the kind of grass-roots-oriented, get-out-the-vote operations that national campaigns need and expect. The typical Columbia-based consultancy is sufficiently competent to produce ads and conduct polls and run basic campaign operations, but it has very few relationships with grassroots organizations — the kind of organizations that in other states might get large numbers of people to show up at rallies or pressure lawmakers to vote for or against controversial legislation.

That’s not the consultants’ fault. It’s just not the way things get done in South Carolina’s political circles. The most effective consultants — some of whom are de facto lobbyists — achieve their aims by a few phone calls to the right people, a few conversations over drinks.

Of course, you can’t win presidential primary contests with phone calls and happy-hour conclaves. You have to have a “ground game.” But South Carolina consultants don’t really do ground games. What they tell presidential campaigns — especially when those campaigns finish out New Hampshire and head for South Carolina and expect high attendance numbers at their rallies — I am not privileged to know. But big, bold get-out-the-vote operations are not really part of the skill set of the typical South Carolina political consultancy, whatever that firm’s website might claim.

Here, I come to the limits of verifiable assertion. But if the consultants hired by presidential campaigns have minimal competence in influencing large numbers to attend rallies and vote in primary elections, some of them — or some of their surrogates — may desire victory badly enough to try other means of gaining votes. In the absence of a “ground game,” perhaps a few strategically placed fliers or well-timed robo-calls might do the trick. Who knows?

All carried out, of course, with plausible deniability.

Barton Swaim worked for Rep. Mark Sanford (R) when Sanford was governor of South Carolina, from 2007 to 2010. Swaim is author of "The Speechwriter: A Brief Education in Politics."