Somewhere in suburban Guam in early 1972, Sgt. Shoichi Yokoi of the Japanese Imperial Army, burdened with shame for having failed his emperor, left active military duty by surrendering to a traffic cop.

It is easy to imagine Yokoi's sense of shock upon discovering that, more than 26 years before, Hirohito had lost his divinity and Japan had lost the war. For all that quarter-century -- without so much as a payday or an office party -- Yokoi, through his unquestioning commitment and his unreimbursed resourcefulness, provided future generations of political volunteers with a new standard and the whole political world with a new rule.

The Yokoi (rhymes with "O-Boy") Rule was first invoked in this country later in that same 1972. In the first national poll conducted after the Democratic convention that July, Sen. George McGovern tailed President Nixon 34 percent to 57 percent. McGovern's elite corps of campaign volunteers, his dedicated "grass roots," heard the discouraging numbers and simply returned to their voter canvassing. They ate and slept less and worked more.

By Election Day, McGovern's percentage of the actual vote cast had climbed to 38 while Nixon's went up to 61. The 23-point gap of July had never narrowed. The battle had been over after Miami Beach and the Democratic convention. But the spirit of Sgt. Yokoi kept the McGovern platoons fighting and surviving.

It is now time to dust off the Yokoi Rule. Edward Kennedy has lost the battle. For him, Madison Square Garden will be the deck of the Battleship Missouri.

It is true, as Kennedy can attest, that challengers to incumbent presidents never truly receive anywhere near parity of press coverage of equal time until the national convention. Only then is the challenger guaranteed at least a couple of cameras and twice as many microphones every time he emerges from an elevator, a coffee shop or the shower.Kennedy wants that time and that coverage. Now is actually the best time for him to use the special chance to "free" his own delegates and announce that he will do nothing for the next three months but work for the Democratic Party to defeat Ronald Reagan and the Republicans; that whatever differences he has with any other Democrat, they are as nothing compared with the Unbridgeable Gap between him and Reagan.

Because, given the present direction of things, in two weeks Jimmy Carter may be envying George McGovern his survey numbers from the summer of '72. The polling data will probably be ignored while the hardy band of Carter partisans cheer each other up by citing the uncanny coincidences between this underdog Democratic president and Harry Truman. Just think of it: Harry Truman and Jimmy Carter -- both Baptists, same number of syllables, vowels and letters in their names. Those are ominous portents you skeptics.

Survivors of the McGovern campaign and the Japanese Imperial Army will, under the circumstances, undoubtedly be kinder than other people. Chances are that representatives of neither group will ever mention the name, rank or serial number of Sgt. Shoichi Yokoi around any Carter storefront headquarers from now 'til Halloween.

If the Yokoi Rule can be suspended in 1980, then at least partial credit must go to the Election Reform Act of 1974. Under that law, both the Democratic and the Republican presidential nominees will receive Treasury checks for $29.4 million. Ronald Reagan has already cashed his.

Jimmy Carter's polls right now are almost twice as bad as the late Hubert Humphrey's were in August 1968. Humphrey did not have public financing to fall back on, but he did have 20 years of credits and shared political foxholes on which to rely in seeking checks and help. He could also raise funds from the "Love Hubert" group, which was concentrated on both coasts but had members almost everywhere.

With virtually no organization and very little of the "smart money" to go along with a personal aversion to asking for money, Humphrey still came within about 48 hours of winning the White House and saving us all from what President Ford called a national nightmare.

Because of the federal subsidy to both the Democrat and the Republican in 1980, poll results do not translate into campaign receipts. If the 1968 rules obtained, Reagan, with his lead and his leanings, probably could legally collect $100 million in the next 11 weeks. Jimmy Carter would be lucky to raise car fare.

If Carter turns out to have a chance to defeat the Yokoi Rule and Reagan, then at least some credit must go to Nixon, whose 1972 crimes made the Election Reform Act almost inevitable.

The champions of the "open" convention (a.k.a. Anybody but Carter, in several precincts), when pressed for the names of alternative Democratic presidential candidates, predictably mention Vice President Mondale, Secretary of State Edmund Muskie, Rep. Morris Udall and Henry Jackson.

One obstacle to a genuine draft for any of these candidates is that all of them have unsuccessfully sought the Democratic nomination in the past. In fact, these four distinguished Democrats, in their aggregate public careers, have not won as many presidential primaries among them as George Bush won this year. The score: Mondale/Muskie/Udall/Jackson (1972-1976), 4; Bush (1980), 5.