Sen. Walter F. Mondale (D) of Minnesota decided in November 1974 that he wouldn't chase the presidential rainbow any more. I thought about that as I watched eight Democratic presidential hopefuls carry on a three-hour debate in Iowa last week. One of them was Mr. Mondale. Polls show he is doing very well in the trial heats before taking on Republican Ronald Reagan.
Why did he withdraw ten years ago? He said frankly: ''I did so on the grounds that I simply did not have the overwhelming desire to do what was necessary in order to be nominated and elected.'' After all, he continued, he liked where he was.
Ten years ago was a turbulent time. Richard Nixon had resigned the presidency and President Ford had pardoned him. Today, Nixon is seeking to come back from his odd role of non-person and is writing books which are received with some embarrassment. And Mr. Mondale? Why he, of course, is running for nomination.
What happened was that Jimmy Carter in 1976 was looking around for an acceptable running mate and tapped his friend Senator Mondale at the Madison Square Garden convention.
In his book ''The Accountability of Power'' Mr. Mondale, in a simple, direct style that is rather attractive expressed his views on the extraordinary process of selecting the president.
About a century ago Lord Bryce, the British ambassador to the US, asked why the United States doesn't pick great men as presidents and asserted that the US parties pick candidates who can be elected rather than candidates who can govern. Mr. Mondale agrees.
Here is what Mr. Mondale, the day before yesterday, said of the system: He called it ''one of the most irrational'' processes he knows. ''It has evolved over barely two hundred years without design, structure, or purpose into a complex maze of state laws, party regulations, and unwritten traditions. No other major nation chooses its leaders in such a chaotic manner, and the question is whether we should continue to do so.''
Some people find a tepid quality in Mr. Mondale but that might disappear if he gets the nomination. He notes that some people discover ''an accidental genius'' in the ''present chaotic nominating process.'' There may be something to this theory, he observes, ''but not much.''
He wrote, ''It's often a mindless process from the candidates' perspective, too often a self-defeating one for the parties, and frequently an ineffective one for the nation.'' He goes on, ''I have been amazed at how little thoughtful discussion and analysis has been devoted to the process of running for the presidency. It is a process, after all, at the very core of our governmental system, and yet there is an inexplicable absence of sophisticated literature on the way we encourage or discourage presidential candidates, on the burdens we impose on them and the hurdles we erect in the path of their nomination and election, and on the relevance of these and other factors to the kind of presidents we ultimately elect.''
This from the man who has tried the thing out and decided it wasn't for him. I do not detect any bitterness in his comments. Perhaps because I agree with his thesis I find his calm, wondering tone disarming. He says ''(I) concluded that the manner in which we nominate and elect presidential candidates is badly in need of fundamental review. The process of seeking the presidency almost defies description. . . . It involves an inordinate period of time, commencing now almost four years before the election.'' Of course it has some virtues, he says. It teaches candidates a lot about America. ''It is a learning process unlike any other.'' The skills and talents developed may assist in the White House afterward. But isn't there a better way? Other democracies look at us in wonder: ''The entire process,'' he says at length, ''needs profound and fresh analysis.'' In fact, he concludes (in 1975), ''the system itself is becoming increasingly irrational, self-defeating and destructive of the ultimate goal of electing the most important political leader in a free society in the world. . . .''
So Mr. Mondale withdrew. ''After 18 months I decided this wasn't for me. It wasn't my style and I wasn't going to pretend that it was.'' That was ten years ago.