With John McCain drawing inexorably closer to locking up the Republican nomination for President of the United States, his ability to unite the party will depend on the proper classification of the struggle he hopes to win.

The morning after Super-Duper Tuesday, the crucial question for McCain strategists and Republicans in general is whether the long battle with Mitt, Huck, Rudy, Fred and the others amounted to an “Issues Primary” or whether it constituted a “Personality Primary.”

In other words, did the intra-party fight represent a struggle of ideas, with the two sides facing an unbridgeable ideological gulf? Or was this contest, like most nomination contests, an argument over which candidate possessed the best combination of ability and experience to represent the party and lead the country.

History shows that nomination struggles fall into one of these two broad categories, and the ability of a divided party to re-unite after a heated struggle depends on which one. In the far more common Personality Primaries, the party often manages to re-unite and win the general election; after Issues Primaries, the party always loses.

The first campaign in which “preference primaries” played a role also represented the first ever Issues Primary—and an unprecedented disaster for the Republican Party. In 1910, Oregon became the first state to establish a presidential primary election to choose delegates to the national convention; two years later, fourteen of the forty-eight states offered such contests and a wildly popular ex-president decided to take advantage of the new system. Theodore Roosevelt, deeply disillusioned with his hand-picked successor William Howard Taft, challenged the sitting president in 1912 in a series of hard-fought primaries and won nearly all of them. While Americans felt great affection for TR’s ebullient personality, the campaign centered on polarizing issues. Roosevelt had moved decisively to the left since leaving the White House, and called for the sort of expanded, muscular, activist government that horrified conservative traditionalists. When the GOP convention in Chicago renominated Taft, and denied Roosevelt the prize he believed he had earned, he launched his famous race with the independent “Bull Moose Party.”

Like all third party efforts, the Bull Moosers failed miserably: drawing only 27% of the popular vote to 42% for Woodrow Wilson and his victorious Democrats. But the hapless President Taft fared even worse – with only 23% of the popular vote in the worst showing ever for a GOP nominee.

The party’s collapse in 1912 established a pattern: when contenders battle over significant issues, offering sharply contrasting policy prescriptions and views of the world, it’s very difficult if not impossible for them to come together in the fall to secure victory.

In 1964, the Republicans split once again over substance rather than style: Barry Goldwater challenged the successful moderate establishment that had ruled the party under Eisenhower and Nixon. In a series of fiercely competitive primary elections the Arizona senator dueled New York Governor Nelson Rockefeller, before securing his final victory in California. The Goldwater Crusade proudly offered “A Choice, Not an Echo” (the title of a bestselling book of the time) and differed from its centrist rivals on the need to confront Communism more aggressively, and to cut back on the ever-expanding welfare state. At the convention, Goldwater delegates actually booed their defeated opponents (including Rockefeller himself) and refused to compromise on platform language or approach. In his acceptance speech, the nominee proudly declared: “Extremism in the defense of liberty is no vice, and moderation in the pursuit of justice is no virtue.”

The Fall campaign adopted a similar tone, with billboards showing Goldwater’s chiseled face along with the declaration: “In Your Heart, You Know He’s Right.” The Democrats responded with a slogan of their own: “In Your Guts, You Know He’s Nuts.” Leading GOP moderates refused to support the ticket, and Goldwater lost 44 of the fifty states, carrying only 39% of the popular vote. Another Issues Primary resulted in electoral catastrophe.

In ’68 and ’72, the Democrats endured their own Issues Primaries with take-no-prisoners struggles over the Vietnam War. First, Vice President Hubert Humphrey captured the nomination after Bobby Kennedy’s assassination (despite the fact that anti-war candidates Kennedy and Eugene McCarthy swept the primaries). Anti-war Democrats never forgave Humphrey, and disrupted most of autumn rallies with raucous chants of “Dump the Hump”—and weary voters turned to Richard Nixon. Four years later, the anti-war forces of George McGovern captured the party and pulled it sharply to the left. While moderate and pro-defense Democrats sulked, the McGovernites (running on the neo-isolationist slogan, “Come Home, America”) carried Massachusetts in November but lost all the other 49 states to Richard Nixon.

In the next two elections, controversial presidents faced Issues Primaries in their own parties—with California Governor Ronald Reagan challenging incumbent Gerald Ford for the Republican nomination in 1976, and Massachusetts Senator Ted Kennedy challenging President Jimmy Carter in 1980. Reagan sought to pull his party substantively to the right, and Kennedy tried to drag his party even further to the left, but in both cases the insurgent candidates lost. Reagan, being Reagan, did his best to re-unite the GOP after his nomination defeat (delivering a singularly inspiring convention address), but President Ford still fell short of victory (losing to Carter, 48 to 50%) After surviving his own issues challenge, Carter himself fared much worse – losing to Reagan in a landslide.

The record of Issues Primaries offers no exceptions: every time a party divides over substantive differences on policy and perspective, it finds it impossible to come together to win.

Personality Primaries, on the other hand, offer far more hope to partisan operatives. In 1960, for instance, John F. Kennedy battled for the Democratic nomination with Hubert Humphrey, Lyndon Johnson and Stuart Symington. These powerful candidates offered huge contrasts in terms of style and charisma, but they never disagreed in any profound way about major issues—allowing Kennedy to lead a united party to its photo-finish victory in the fall. Similarly, the rock-em-sock-em 2000 battle between Arizona Senator John McCain and Texas Governor George Bush generated plenty of heat with its contrasting personalities, but the two contenders scarcely disagreed on major issues. Both tried to appeal to the broad center of the GOP and the electorate at large: in fact, when McCain gained traction with his mantra of “Reform,” Bush countered that appeal by proclaiming himself “A Reformer With Results.” In a personality primary, the defeated candidate usually manages to overcome his disappointment and campaign for his one-time rival – as McCain did for Bush in 2000, and again in 2004.

Perhaps the classic example of a Personality Primary involved the Democratic contest of 1984. Colorado Senator Gary Hart offered the party a younger image, and much better hair, than former Vice President Walter Mondale, but the two men agreed on virtually every major issue. The lack of substantive conflict seemed so apparent that Mondale won the battle by asking, “Where’s the Beef?” about his rival’s challenge. In the absence of significant distinctions on important issues, Mondale successfully argued that his experience and seniority trumped Hart’s freshness and good looks.

In terms of anticipating the shape of the final campaign of 2008, it makes a world of difference whether the nomination struggles among Democrats and Republicans deserve description as “Issues Primaries” or “Personality Primaries.”

On the Democratic side this year, the classification ought to be obvious: the battle between Hillary and Barack is all about personality, with scant argument about issues. Though Obama tries to focus on the fact that he opposed the Iraq War years before Senator Clinton turned against it, voters understand the fact that the two candidates now agree on the same dovish policy (with sneaky qualifications for both of them, but that’s another story). On medical care, their plans match so closely that they’re reduced to debating minutia – like Hillary’s mandate for all citizens, but Barack’s mandate only for all children. This is not the sort of implacable disagreement, the “irrepressible conflict” (in Lincoln’s phrase) that divides great parties.

In short, there’s good news here for the Democrats: their contest remains, clearly, a Personality Primary after which the two foes will manage to come together (and perhaps even share the ticket) to confront the Republicans in November.

But what about the Republicans?

Their chances for general election victory depend upon clarifying the contest’s status as a fight about personality, more than a fight about issues.

In fact, the leading candidates do agree on virtually every important policy for the nation’s future – both McCain and Romney want to persevere in Iraq till victory, to use force if necessary to prevent a nuclear Iran, to treat Islamo-Nazi terror as the profound evil it is, to shrink the size of government and to lower taxes. Both candidates want to curb abortion and defend innocent human life, protect gun rights, and preserve the institution of male-female marriage. Both seek to provide better access to cheaper health care by moving toward a more market based medical system, not through more government. On immigration, both candidates have taken notably tougher positions than they did a year ago, and agree on the need to secure the border first (by finishing the fence and hiring far more border patrol), while improving national ID and greatly enhancing workplace enforcement. As Governor Romney explicitly acknowledged at their South Carolina televised debate, on the top immigration priorities, there’s no meaningful distinction among any of the major candidates.

Their positions on issues remain so close that I can reproduce part of the official “candidate’s statement” from the State of Washington Voter Guide and you can’t be sure which of the GOP contenders authored it:

“At home, Americans have lost trust in their government. To restore their trust, I will secure our borders, veto pork-barrel bills, keep taxes low and reform our tax code. I will nominate judges who do not legislate from the bench. I will seek to modernize Social Security, Medicare and Medicaid, bring choice and competition to our schools.”

Okay, quiz kids, which Republican contender authored those sentences? Romney, Huckabee or McCain?

The point is, it could have been any of them, so it’s hardly significant that the right answer here is …. John McCain.

If there’s so little difference on the big issues facing the party and the country, how can one possibly explain the frenzied hostility from some conservatives to Senator McCain? The fact that these angry voices want to dredge up long-ago disagreements with no current relevance indicates that their real object involves personality, not substance. The issue of the McCain-Feingold Campaign Finance Reform, for instance, was settled seven years ago and no candidate wants to repeal the legislation. In other words, in terms of policy, there’s no difference at all between the candidates--- Romney doesn’t want to repeal the bill, and McCain doesn’t want to extend it.

Instead, McCain critics bring up the issue as a way of emphasizing their distaste for McCain’s “maverick” personality, his willingness to work with Democrats to achieve his policy goals. At the same time, they don’t acknowledge that on key goals that McCain, Romney and Huckabee share – like reforming Medicare and Social Security, for instance—no progress is vaguely possible without precisely that sort of cooperation with the leaders of the other party.

McCain’s personality remains a problem --- many conservatives find it insufferably obnoxious, some of us view it as candid and refreshing.

But on key issues, Republicans of 2008 face no wounds that can’t heal, no gaps that can’t be bridged.

If you doubt this proposition, think about the platform: there’s no real threat of a platform fight because McCain, Romney and Huckabee could all run with equal comfort and enthusiasm on a statement of plans and principles that proclaimed mainstream conservative values.

In the aftermath of Super-Duper Tuesday, with Mike Huckabee’s surprising success (predicted by this commentator, and almost no one else) should remind Republicans once again that there’s no big division on issues in this year’s GOP. Is Huckabee a stout-hearted Christian conservative who took conservative votes away from Romney, or a big government populist who took moderate votes from McCain, or a little bit of both who took votes from both? The fact that different commentators can make a convincing case for each of the three alternatives suggests that the renewed Huck-a-boom concerns style and personality (and peerless communication ability) far more than policy substance.

Despite the gloom in some circles at McCain’s coast-to-coast success in the February 5 primaries, even disaffected activists should take heart at the proper identification of this nomination contest. McCain should do whatever he can to emphasize that the struggle in which he looks increasingly like the victor was never about important differences on vital issues, but rather involved spirited debate as the right individual to implement the same approaches. All three candidates express similar conservative outlooks and should begin the process of working together after the conclusion of a tough fight that has been, after all, a heated but typical Personality Primary.