Rigid application of past outcomes to changed circumstances signals lack of understanding. So word that the president plans to announce for the Mideast and Central Asia a doctrine akin to that put forward by President Truman for Europe not only smacks of public relations; it also suggests preparations for fighting the last war. It recalls the comment by the Duke of Wellington about a troop of recruits: "I don't know if they will frighten the enemy, but, by God, they certainly frighten me."

Still, those who have urgent a more realistic foreign policy featuring stronger barriers to Soviet adventurism cannot simply stand and wait. Events are now on the move. President Carter is in the White House for at least a year more -- maybe five.

So the test is not whether he suddenly takes on new rhetoric. It is whether he begins to surround himself with associates equal to the new tasks. For those who brought us into the present mess are not those who can best get us out.

Secretary of State Cyrus Vance has been the foremost proponent of detente with Russia and arms control at any cost. At the undersecretary level, he has taken on colleagues chiefly remarkable for being moons tht do not outshine his sun. Policy-making at the department has devolved chiefly upon regional assistant secretaries. Those responsible for Asia and the Mideast and Africa have been notorious for their conviction that the United States had to let down old friends the better to accommodate radical regimes.

Secretary of Defense Harold Brown has concentrated on procurement issues and deferred on policy matters to Vance Brown delayed for months before filling the post of undersecretary for policy. Even now, the incumbent, Robert Komer, has been barred from responsibility in that political hot spot, the Mideast.

As director of central intelligence, Adm. Stansfield Turner has had virtually no impact on policy -- and not merely because the CIA has been hamstrung by congressional rules either. Turner, like most of the top brass of this country, prefers machines to men, and shies from covert action of a political kind. Judging by the stream of CIA documents distributed to the press, his working motto is "Publish or Perish."

The president's special assistant for national security, Zbigniew Brzezinski, well understands the threat of Soviet expansion. But he has no allies in the bureaucracy and tends to favor rhetoric over operations. He has lost battle after battle to Vance, and is void of impact on the execution of policy.

The inability of the old gang to develop new measures finds abundant expression. The response to the invasion of Afghanistan was convulsive, not smooth. No consensus was built in this country. Allies in Europe were surprised and not ready to rally 'round. The Third World countries most wooed by President Carter -- witness the abstention of Mexico in the recent U.N. Security Council vote on economic sanctions against Iran -- did not support him. The Russians had reason to feel that the United States, as Leonid Brezhnev put it, had been "an unreliable partner."

The operational follow-up has been unimpressive. Pakistan is being offered long-term aid when it asked for what amounts to an immediate security guarantee. China is being fed words, not weapons. The countries of the Persian Gulf are asked to sign up for bases that are -- somehow -- not bases. pThe CIA, instead of being subject to less complex regulation, is going to be put under a charter.

If reelected, Carter will have to make wholesale changes. For the time being, a total purge is out. But there are some places where the president can begin to make a dent.

He would pay no price for replacing Turner with someone more versed in projecting American political influence abroad. He would add new strength if he placed under Brzezinski in the National Security Council a genuine crisis manager. Similarly if Komer's writ as undersecretary of defense for policy were made to run around the world.

New men for new measures are required not merely as a gauge of the president's serious intentions. The fact is that the United States is starting to traverse a danger zone. Regimes up and down the Persian Gulf, and particularly in Iraq, Iran and Afghanistan, could easily come apart. The chances of Russian overreaction or miscalculation are not small. So there is intense need for foreign policy advisers who act out of instinct and with conviction -- not by trying to remember what was done by Harry Truman.