Distance runners and coaches have an expression: “That’s why we run the race.” There’s nothing foreordained about the outcome of any given competition. One athlete can be heavily favored based on past performances and still lose to someone else whose months of training pay off at the end of the season.

Remember those pundits in August who said the presidential primary had become a two-man contest between Mitt Romney and Rick Perry? Oops. That’s why we run the race. Remember how Newt Gingrich was done in June when his staff quit? That’s why we run the race.

What if Romney had screwed up? Running for President is harder than it looks. Giving credit where credit is due, Romney has run a nearly error-free campaign, especially in New Hampshire. He retained nearly his entire organization from four years ago. He locked down more endorsements than the rest of the field combined. He avoided antagonizing conservative and Tea Party activists. He showed incredible discipline in every aspect of the campaign and paced himself well. If another candidate was going to catch him, it wouldn’t happen because of an unforced error by the Romney machine.

What if Romney had won the primary last time? If Romney does go on to become President, it will happen in no small part because he lost the 2008 New Hampshire primary. Think about it: Had Romney defeated John McCain here last time, Romney likely would have become the Republican nominee who lost to Barack Obama that year. A defeated nominee hasn’t been given a second chance by either party since Richard Nixon in 1968. Losing in 2008 might prove the best thing that ever happened to Romney politically.

What if Gingrich had spent more time campaigning in New Hampshire in December? If Gingrich is disappointed on Tuesday, many will question his absence from the state in the weeks following this paper’s endorsement. That event occurred Nov. 27. In the following five weeks, Gingrich made only two visits to New Hampshire, one of them to collect House Speaker Bill O’Brien’s support. Gingrich did not fully harness the surge of interest in his candidacy last month.

What if the Tea Party consolidated behind one candidate, early? Gingrich did succeed in coalescing many Tea Party activists, something several other candidates had attempted, and failed, to do. But before that, perfection-seeking Tea Party groups couldn’t settle on their preferred candidate. For all the talk about the expected influence of the Tea Party on the nomination process, in the end they have had very little impact.

What if Perry hadn’t run? Perry proved to be a truly lousy candidate, one for the Underachiever Hall of Fame. How did he get elected governor of Texas? But before he flopped, Perry locked down a lot of New Hampshire activist talent — and kept those people away from Gingrich or Santorum, where they could have made a difference.

What if Jon Huntsman had run as a maverick? McCain won the last primary with 37 percent. His coalition wasn’t based on ideology but rather on his image as an independent-minded maverick willing to take on his own party. Surprisingly, none of the candidates attempted to rebuild the McCain coalition. The candidate who might have successfully done so was Huntsman.

What if Tim Pawlenty hung in there? Pawlenty obviously made a fatal error in competing in the Iowa straw poll — no credible candidate will ever make that mistake again — but he probably would have recovered and found a second wind, like McCain and Gingrich did, if Pawlenty hadn’t given up.

What if Sarah Palin had run? Palin flirted with a candidacy as late as June but she made the right decision not to run. Polls showed her losing badly to President Obama in hypothetical matchups, and the Republican electorate is in no mood to re-elect this President by nominating someone who can’t win. A Palin candidacy would have ended the same way Michele Bachmann’s did.

What will happen on Tuesday? Five candidates have a shot at meeting the 10 percent threshold that earns them at least one delegate coming out of New Hampshire, but only three will. Romney and Ron Paul will be two of them. Who will be the third? Can’t be sure. That’s why we run the race.

Fergus Cullen, a freelance columnist, can be reached at fergus@ferguscullen.com.