JIMMY CARTER'S presidency has enshrined a law of contemporary politics that seemingly governs those who govern: For every vision, there is an equal and opposite revision. Not that he bears sole responsibility--he is at once a product and an extension of the politics fashioned by the media and the polls. He cannot automatically be condemned for conducting his presidency like a campaign and his campaign like a president. More dangerous are the roots of his present posture, a stance much different from that of four years ago, when he rode a wave of superficial optimism into office. Carter is practicing the politics of pessimism, needlessly, and his very negativism may sweep him out of the White House--his crisis of confidence supplanted by Ronald Reagan's crisis of overconfidence.

Four years ago, Carter thought it appropriate to ask America two questions in his paperback. "Why Not the Best?":

Can our government be honest, decent, open, fair and compassionate? Can our government be competent?

Sadly, "Why Not The Best?" has not proved to be a rhetorical question over the last four years. But it would be too easy for a pundit to point cynically at Bert Lance as an example of "honesty", Billy Carter as "decent", Presidential Directive #59 as "open", the president's unwillingness to debate as "fair", the induced recession to combat inflation as "compassionate", and Carter's overall record as "competent".

Carter's blatant politicking while in office has sown the seeds of paranoia, a tension of the type he claimed he would dispel. Who knows what U.S. foreign policy is exactly? Is the Georgia clan running the country? More conspiratorially, some have wondered if Carter deliberately induced the recession knowing the slump would tail off and conditions would be "improving" around election time. Perhaps that scheme seems ridiculous, but such is the psychological atmosphere--and it only represents relativistic politics taken to a logical extreme.

It is not likely Carter cooked up such a strategy. But that it does not defy the imagination underscores Carter's main weakness as president: he has not led, he has been led. If citizens agree with the president's own refrain that there must be "no acceptance of mediocrity in any aspect of our private or public lives," then Carter will surely lose in November. But once layers of rhetoric are peeled away--words should not obscure reality--citizens may be confronted with the disturbing notion that Carter represents quite accurately their attitudes. He has reflected a certain ambivalence, an ambiguity in direction. If he has lurched from difficulty to difficulty without a coherent design, if he has wavered between two extremes in both economic and foreign policy, it is only because he keeps one eye cocked at public opinion polls. At every instance, he has not acted but reacted.

SEVERAL CARTER BACKERS claim that is what democracy is all about--a president should just comply with the will of the majority at a given time, even when the nation seems unsure of where it wants to go. But why have a president if his sole purpose is to effect the tyranny of the polls? By his unwillingness to provide leadership, Carter has unwittingly paved the way for the resurgence of conservatism, allowing well-organized interest groups with narrow bases of support--like anti-ERA forces--to arrogate to themselves political power through sheer zeal.

Carter's presidency has frozen government into stasis. Paradoxically, Carter gained power largely because of fragmentation of power, a fact duly acknowledged by Press Secretary Jody Powell in David Broder's latest book. The system has worked: Carter has fulfilled the prophesy of 1976 campaign chronicler James Wooten, who noted in "Dasher" that

Carter was quick to notice that, in politics, it is often just as important to be perceived as something as actually to be that something and, as a matter of fact, that one need not be anything ideologically at all.

We could forgive Carter his lack of ideology if he governed effectively. Whereas his predecessors in the TV age governed by straddling the two prominent wings of American politics, Carter--to be sure, in less prosperous times--finds himself in a saddle without a horse. The center has eroded. As Carter's supporters justifiably point out, there are dangers inherent in cleaving too closely to a set doctrine, a grand design; consensus politics have not always produced desirable results. In a fit of frustration, White House domestic adviser Stuart Eizenstat admitted to Broder that he longed for a parliamentary system. This amounts to a revealing response to Carter's second question, "Can our government be competent?" and it comes from the president's top domestic consultant.

IN THE DOG DAYS of this enervating campaign, it has become fashionable to gaze wistfully north and draw analogies to Canada. Former presidential candidates such as Sen. Howard H. Baker (R-Tenn.) have called for a shortened campaign, referring to the recent Canadian elections. In the space of a few months, Baker noted, one government fell, a federal election was conducted, and a new government installed--while American hopefuls were focusing on the New Hampshire primary. Of course, the parallel breaks down; in Canada, the party leaders were firmly in place and had only to face each other, a mere nine months after the previous election. Still, for Canada the process was healthy. Issues were focused and debated, stances clearly enuniciated, and the voters given a less blurry choice than Americans will have in November.

For a worthwhile history lesson, Carter might consider the May 1979 Canadian federal election. Incumbent Prime Minister Pierre Trudeau and his Liberal Party had held power since 1968. The strategy of the campaign was to focus attention on Joe Clark, the inexperienced and unimpressive leader of the opposition Conservative Party. Trudeau attacked Clark relentlessly, but neglected to provide a reasonable, positive agenda for the country.

Most Canadians recognized Trudeau's leadership capacity as superior to Clark's. But Clark presented himself as "of the people," pointed at 11 years of Liberal government, and won the race. There was an "Anderson factor" as well--the socialist New Democratic Party split the vote of the left with the Liberals, putting Clark in power through the back door. Nine months later, Canadians tired of Clark--as the United States might grow weary with Reagan after nine months-and reelected a majority Liberal government after Clark ran an anti-Trudeau campaign.

PERHAPS, THEN, Jimmy Carter should reconsider his politics of Pessimism, and recognize that he will not win by projecting a "lesser of two evils" image. If liberals and moderates reject Reagan as dangerous, and fear Anderson will siphon off enough Democratic votes to propel Reagan into office, Carter must make himself an acceptable choice, rather than a weak alternative.

To date, Carter has not seized the initiative, in the process underscoring all his familiar failings as a leader. Here are some things he might consider: Taking part in the presidential debates, as any responsible leader would; apologizing to Iran for past indiscretions, as any brave head of state would; sticking to his own party's platform, as any democratic leader would; implementing a foreign policy that defends human rights in practice as well as in theory; increasing aid to less developed countries; giving America's allies at least some confidence that he will stick by them; renewing his commitment to SALT II; and forging new initiatives in social programs.

Then, maybe, Carter will prove acceptable to liberals, to all Democrats and to the country's center. He will get their votes when he deserves them. They want nothing more than a viable candidate of whom their consciences will approve. As it stands, a victory is not forthcoming, and if it were, it would be an empty one. As the man responsible for the politics of pessimism, he is the man responsible for restoring the politics of hope.