The newest reason being advanced for Jimmy Carter's apparent ineffectuality is his Christian conscience. He is too religious a man, they say, to be decisive in the exercise of power.

he unstated premise is that our society is so anti-Christian in its values and so barbaric in its institutions that no truly moral person can hold high office in the government without peril to his or her immortal soul. This is the presidency-as-an-occasion-of-sin school of thought and, while there is little to be said for it, such attempts at applied theology at least have the virtue of being serious minded. It's a step up from the gossip columnists' analysis that Jimmy Carter's trouble lies in the fact if needed it is a fact, that his White House aides don't go to dinner in Georgetown often enough.

The Prestigious Peanut's troubles don't arise from Christian indecision or a vacillating character. The man knows how to make up his mind. His problem is that when he makes his mind up, he lacks the power to compel other people's attention. Much about the presidential office is glorious, golden bluff and the men who have occupied it most happily, those whom we look back on as leaders, are those who could pull the imperial con on the people they wished to move and mobilize. Part of doing that is a talent and part of it is an acquired skill, but nobody can bring it off when the circumstances are wrong. Even Franklin Roosevelt, who is rightly revered as a master of the art of being president, got his political fanny kicked more than once.

Sometimes presidents may lead without seeming to, Newspaper editorialists and other worshippers of melodramatic monimania equate leadership with looking like Winston Churchill. If you can't give off with the gruffy eloquent bulldog snorts against a panoramic background of burnning cities you ain't no leader, Bub. A man like John Kennedy was particularly disposed to thinking this way which explains the dangerous mock heroics and egocentric theatrical poses of the famous October Missile Crisis. A president with a less operatic definition of courage could have handled the matter just as as successfully but in a manner so mild and mundane it would have been remembered by diplomatic historians and few others.

If Carter had flaunted the Churchillian leadership s often demanded of him in the Middle East situation, the results would have been terrible. This has not been an area in which to strike the bol profile. Leadership has been less necessary than guide-ship, if I may be permitted one ugly neologism. American has had to be noodged, not challenge, into a new approach.

In a quiet way, Carter has set things up so that millions of heretofore pro-Israeli Americans have come to see that the prime minister of that angry little militocracy considers every inch of foreign ground his army occupies his by right of conquest. If Carter had made a set speech making that accusation, he would have detonated a controversy that would have retarded the growing recognition of Israel as an aggressor state. By being temperate and giving Menachem Begin as much TV airtime as he wants, he has let the prime minister do a job on himself. That may not be flashy leadership of the sort that gets you a post-mortem statue in the park, but it gets the necessary political job done and done with a degree of art.

Jimmy the Baptist has had to work around other difficulties in the slow business of moving American foreign policy to a new position in that part of the world. He has had to begin the job of pulling free from the worst kind of alliances bequeathed to him by all his immediate presidential predecessors. This is the open-ended infinite alliance with a small nation that has been given the power to make America ratify and back up its faits accomplis.

Written treaties can get us into the most devilish entanglements but unwritten, pseudo-sacred commitments are worse. Their very vagueness puts us in the position of appearing to agree to any act, no matter how barbaric, committee by our very junior partners. Thus in the Lebanon situation, we've been in a painful trick bag. Either we support the Israeli heavy artillery bombardment of an open city or we break off our relationship with Tel Aviv altogether.

Carter had been looking for a third way. The way he has chosen is to wiggle. It is midly inglorious and it also involves selling jets to Egypt and Saudi Arabia, who shouldn't have them either, but he has the peanut in front of his nose and is rolling us away from a policy that is not only morally dubious but has imperiled a major source of oil. Not bad for a man paralyzed with an overly scrupulous conscience.