DES MOINES When Pat Buchanan quit the Republican Party this fall and started running for president as a Reformer, he darkly threatened a legal war with the one entity that has earned the public's trust in presidential politics - the Commission on Presidential Debates. Include me in this fall's general election debates if I'm the third party's nominee, Buchanan warned, or I'll sue.
The next words out of Buchanan's relentlessly working mouth several days later on the subject were quite different. This time, he said that if 15 percent of the likely electorate has warmed to his message in the national polls, the commission will be forced by the political facts of life to include him.
In part Buchanan was recognizing legal reality. Despite all manner of legal and political obstacles, the commission's track record is perfect. The courts have without fail upheld the bipartisan organization's statutory authority as well as its exercise of that authority. It is regarded as scrupulously fair legally because in fact it is.
But Buchanan was also recognizing political reality, broadly defined. The general election debates are now legitimately special. They have the feel of finality as the country nears its decision. And their essence is the credible impression that on stage are the only people with a ''chance'' to be elected president.
Some people are trying to make the same point about intraparty debates as the Republicans' and Democrats' nominating caucuses and primaries approach, and they're wrong. It's bad enough that a battle for big shots' big bucks has become the field-winnowing first primary of the season; to have elites further limit the nomination contest would be an abomination, further tarnishing the meaning of the prize.
As the preparations were being made for last night's GOP affair in the big civic center complex that graces downtown Des Moines, what was in the air was the faint whiff of instability. This is a party with multiple factions - social conservatives, economic conservatives, moderates, and populists. Each of these factions challenges the front-runners intellectually and personally as well as for actual votes. They are integral elements of the testing process that can confer legitimacy on the ultimate decision of voters, not to mention the entertainment and political value of a trenchant question or challenging answer.
To throw out Gary Bauer, Alan Keyes, or Orrin Hatch at this point - as some Republicans who prefer order too much argue - would be to impose a choice more than to clarify one.
There is irony, to be sure. George W. Bush has a right to wonder at the odd elements of democracy as they have affected his alleged juggernaut. When he was more or less hiding, his position was seen as unassailable by a political community in love with and blinded by money and endorsements. As he descended from Olympus, perceptions have changed.
That's tough, but fair, and even the most order-fixated Republican must agree that it's better to find out what a front-runner is made of now than smack in the middle of the general election. It's better to let all the excited Republican people outside the hall waving signs for their guy know that he has a chance to be heard inside the hall and on television.
In a few weeks - just as decision time nears in Iowa and New Hampshire - the debate commission is planning to unveil its all-important criteria for inclusion in the fall debates. The likelihood is that they may change some from 1992 and 1996, primarily toward something easier for the public to understand, more nearly automatic, and less subject to interpretation but still focused on the only question that should matter come September - can Candidate X be president or at least deny the others an Electoral College victory?
In the past, with the Federal Elections Commission doing the formal certifying, the statutory requirement of objectivity included 11 criteria used by the debate commission's advisory panel. Chaired by the greatest of all the presidential scholars, Harvard's emeritus professor Richard Neustadt, they focused on the Electoral College. That meant that as Neustadt did his work before each debate, the key question was whether a candidate was in realistic position to win any state.
That question may change toward some simpler point about national poll standings (Buchanan's 15 percent isn't bad), but the fundamental point about electability or ability to deny victory to the others should remain. The danger always lurks that a low bar will prompt one of the so-called major party nominees to balk at participating, as Jimmy Carter did with John Anderson 20 years ago when the League of Women Voters was in charge.
In 1992 Ross Perot spent May and June in a tie with George Bush and Bill Clinton. Even in the fall, hovering near 20 percent, he was in position to matter. Four years later, with half his support gone, he wasn't.
Since 1987 the debate commission has been cochaired by the same selfless Republican (Frank Fahrenkopf) and the same selfless Democrat (Paul Kirk) and run by the same dedicated Republican, Janet Brown.
They have put on great shows. They have gradually gotten rid of preening reporter panels and substituted questions from citizens as well as direct exchanges among the candidates. Their research shows that the public sees the debates as ''theirs,'' not the parties'.
We should all hope this continues through another election cycle.
Thomas Oliphant is a Globe columnist.
