On Aug. 11, what Jimmy Carter needed almost as much as his mother's confession that Billy has a twin brother in Perth Amboy was the publication of a news magazine's survey of 46 governors on who would carry their states in November.

Right now there are 31 Democratic governors. Last summer in Louisville, they overwhelmingly endorsed Carter for renomination and reelection. They have remained constant to their former colleague through his trouble.

Governors are practical fellows. They do not in the normal course of things spend much of their time reflecting on the efficacy of the nuclear umbrella. Governors have been known to concern themselves with horse racing dates, interstate routes and even appeals court appointments. Congress may decide how much will be spent on interstate highways, but governors have a much larger say in whether the new access ramp goes through my gas station or your back yard,

Nine of the governors -- all Democrats -- told U.S. News that Jimmy Carter would beat Ronald Reagan in their states today. Thirty-five governors said Reagan was ahead in their states.

A poll like this can be unhelpful at any time. It is not scientific, but it is just one more indication that Jimmy Carter will start this campaign as the Lone Ranger, with other Democratic candidates remembering "previous commitments" when his headquarters calls with requests for joint appearances.

But what it raises for the first time for some Democrats here in New York is the scary possibility that Ronald Reagan may be so far ahead of Jimmy Carter by early October that the Reagan people will not have to worry about losing the presidential race. If that is the case, then the Republicans and Reagan will have the option -- for them, the delightful option -- of simply targeting Senate seats and congressional districts for the last four weeks of the campaign. It would free Reagan to concentrate on 45 House races and Senate seats, in places like Idaho and Indiana. Reagan could make a large difference -- and that is making some Democrats very nervous.

Darrell Royal, the very winning former University of Texas football coach, actively disdained the forward pass as an offensive tactic. When asked whether his Texas team would pass more in the Big Game the next day, Royal always answered no by saying, "We're going to dance with the girl who brought us."

In their fight, Jimmy Carter and Edward Kennedy were practicing disciples of Darrell Royal. Both faithfully pursued the same strategies that put them in the position of being the only two Americans who had delegates pledged to them at the 1980 convention.

For the senator, this took the form of his unstinting commitment to public action, government programs and "the old, the young, the women and the minorities." Kennedy obviously believes that repetition is the first law of teaching; he recited those things before microphones at least 47 times daily.

For the president -- the outsider who beat the face cards of the Democratic Party in 1976, the man with no Washington experience to taint him -- this is the faith that you can tactically go home again. A week ago, before a couple of hundred of his delegates at the White House, Carter, some 43 months in office, said to his assembled troops: "Let's not let the party bosses control our party." As anyone can plainly see who's around where there used to be clubhouses and bosses, there aren't any left. No pinky rings, no white-on-white shirts and no short guys named Lefty who could always deliver the 11th ward. But both Carter and Kennedy stuck with what worked.

One of the shrewder political rules urges parties or candidates to do those things their opponents can't. If your opponent is fat and out of shape, challenge him to a softball game and invite the television cameras. That sort of thing.

Well, that old rule certainly was practiced faithfully by Rep. Morris K. "Mo" Udall last night, as he must have noticed humor did not have a floor pass to the Joe Louis Arena during the Republican convention.

Thanks to Udall, the Democrats who do not have an awful lot to be happy about right now at least had something to laugh about last night. Mo Udall never subscribed to the Mournful School of Political Activity. It has, for the last decade commanded a large Democratic following that insists that, to care about any issue one has to be sorrowfull really care. Mo Udall has always managed to take his cause seriously, but not himself.