Elections are highly instructive. While no two are ever the same, data points from individual races can be used to draw general conclusions. Last week’s Republican primary between U.S. Sen. Lindsey Graham, R-S.C., and his six challengers is a case in point.

A key question is whether or not fielding multiple candidates against an incumbent is an optimal strategy. On one level, since Graham won the answer is obviously no.

But given South Carolina’s primary run-off system, fielding multiple challengers – instead of a single candidate – has certain theoretical advantages:

Multiple candidacies encourages separate contests in the state’s various geographic regions, allows for greater experimentation in defining effective messaging, prevents incumbents from unloading their war chests against a single challenger, and gives activists time to pick the strongest challenger during the “pre-primary” period.

Strategically, the goal was to hold Graham under 50 percent in the primary, and then rally behind the leading challenger in the run-off.

One assumption held true: the leading challengers had well defined geographical strongholds. Though Graham carried every county, identifying who came in second place by county reveals significant patterns.

State Sen. Lee Bright, with 15 percent of the vote statewide, placed second in two widely separated clusters of counties in the upstate (including his home county of Spartanburg with 33 percent and Greenville with 27 percent) and in the low country around Charleston, Berkeley and Dorchester.

Richard Cash (8 percent statewide) ran for Congress in the old Third Congressional District in 2010. Predictably, he placed second and received 17 percent in those counties, including Edgefield (34 percent) and Aiken (17 percent).

Det Bowers (7 percent statewide) was second in Sumter, Richland and several rural counties including Hampton, Allendale and Jasper along the Savannah River and Fairfield, Lee, Dillon and Georgetown in the east-central region of the state.

Bill Conner (5 percent statewide) was second in a narrow swath of counties between Columbia and Charleston, including Orangeburg and Florence.

Neither Nancy Mace (6 percent statewide) nor Benjamin Dunn (1 percent statewide) had any concentrated support, though Mace broke into double digits in Berkeley and Dorchester.

Yet this strategy broke down at several points. The six candidates tried to expand their regional efforts statewide, thereby frittering away their resources and creating confusion among anti-Graham voters. Multiple candidacies discouraged support from conservative PACs. No candidate emerged during the “pre-primary” as the leading challenger.

Most importantly, though Graham had no one challenger to barrage with negative advertising, he did launch effective positive advertising and direct mail campaigns to refurbish his image among Republican voters.

Graham received 56 percent of the vote versus 44 percent split among his six challengers. Though his margin was much lower than his 66 percent victory over Buddy Witherspoon in 2008, a win is a win.

Interestingly, if each of the six challengers had received about 1 percent more of the vote at Graham’s expense, a run-off would have occurred. Alternate history, however, doesn’t win elections.

But what about the five counties that Graham “lost” by receiving less than 50 percent of the vote? What happened there that didn’t happen statewide?

Graham received 39 percent in Edgefield, 41 percent in Greenville, 47 percent in Laurens, 43 percent in Spartanburg and 48 percent in Union. Cash finished second in Edgefield and Bright finished second in the other four counties.

(Aiken County was almost, but not quite, on this list: locally Graham received 51 percent.)

Several factors produced those atypical outcomes. First, in these counties the leading challengers received percentages significantly above their state averages. They were within Bright’s and Cash’s electoral strongholds.

Second, these five counties fall north and west of an arc running from Aiken to Lexington to York. This is the most conservative quarter of the state, best known for sending Jim DeMint, Gresham Barrett, Jeff Duncan and Trey Gowdy to Congress. Including all of the Third and Fourth Congressional Districts and parts of two others, this is South Carolina’s conservative heartland.

Third, these counties contain several effective conservative grassroots organizations, which partially offset Graham’s fundraising advantage.

In hindsight, a smaller field of challengers would have improved the odds of a run-off: a greater chance for a leading candidate to emerge (like Chris McDaniel in Mississippi’s run-off election against Sen. Thad Cochran), more concentrated fundraising, and less dispersion of effort.

Politics is an empirical business, and understanding what does and does not work is essential to victory. There’s no doubt that the lessons learned from this race will be closely studied by candidates and their consultants.

Gary Bunker is a former Aiken County Councilman.