A year ago this month, Ronald Reagan met with his Cabinet and senior White House aides to assess his situation. Control of the Senate had just swung from the Republicans to the Democrats. The Iran-contra story was beginning to unravel. And the candidates for the 1988 presidential election were elbowing forward, signaling the approaching end of Reagan's tenure.
The message that emerged from those meetings, a former Cabinet member recalled last week, was embodied in the slogan: ''Lock in the Reagan Revolution.'' Any effort to undo what Reagan had accomplished in his first six years was to be resisted. Any opportunity to institutionalize the changes -- to secure them against tampering by Congress or the next president -- was to be seized.
The reflex to dig in and fight was perfectly understandable. But the clear implication was that 1987 would be a year of confrontation for the chief executive. And now circumstances have forced Reagan to abandon that general posture for one of conciliation and consensus-seeking. The result may be to diminish Reagan in the eyes of the ideological cadres but to enhance him as an asset for the Republican Party in 1988 and perhaps secure his legacy in a different way.
The ''lock in the revolution'' strategy was clearly embodied in the January Reagan budget, which slashed at domestic spending and tried to reaccelerate the slowing Pentagon buildup. It was evident in the State of the Union address, which laid down a hard line on continued support for the anti-Sandinista ''contras'' and the development of the Strategic Defense Initiative. It showed in Reagan's quick vetoes of the highway bill and the Clean Water Act. It surfaced again later in the year in the effort to promote ''an economic Bill of Rights,'' including the balanced-budget amendment and line-item veto authority. And it was the underlying motive in the effort to place Robert Bork and later Douglas Ginsburg on the Supreme Court.
There was nothing sneaky or dishonorable about the confrontation strategy. But it has failed, and now it is being changed. Reagan is trimming to meet the altered circumstances of his presidency, acknowledging last week that recent experiences ''have made us all a little wiser.'' You can see the change in his selection of Judge Anthony Kennedy as the fallback candidate for the Supreme Court vacancy, in his belated willingness to negotiate a budget compromise with the congressional Democrats, in the decision to postpone a request for new funds for the contras.
For Reagan, the lessons began painfully. The Iran-contra affair undermined much of the public support that gave him political leverage in Washington. It put the administration on the defensive for 10 months, sapped the White House's energy and, for a time, quenched Reagan's own optimism and assertiveness. It also forced an overhaul of the White House, including the dismissal of the combative Donald Regan as chief of staff and the substitution of former senator Howard Baker, an instinctive conciliator.
The second unanticipated circumstance was the vigor of the political opposition, notably the new speaker of the House, Jim Wright of Texas, and the band of younger moderate-liberal Democrats in the Senate. Unlike his predecessor, Tip O'Neill, whose anti-Reagan bark was worse than his bite, Speaker Wright clearly has delighted in ripping up Reagan. And he has found many occasions to indulge his appetite.
In the Senate, George Mitchell of Maine and the southern Democrats he helped elect last year in his role as chairman of the Democratic Senatorial Campaign Committee have brought new brainpower and backbone to that flaccid body -- as was evident in the Iran-contra hearings and the Bork fight.
Third, the sudden, severe wobble in the economic picture following the October stock market nose dive made it evident that the cost of continued political confrontation in Washington might be the wreck of Reagan's most important domestic achievement: the long period of inflation-free economic growth.
And finally, as Reagan's hopes came to center increasingly on a Soviet-American arms-control agreement, the case for conciliation became overwhelming. With many hawkish Republicans deeply skeptical of this new ''de'tente,'' it has become clear that ratification of the treaty will require strong Democratic support. Cooperation in that area makes it more difficult for Reagan to be confrontational in others.
All this may make some true believers think that Reagan is in full retreat. But in fact, he has had and can continue to have significant impact in each of these areas of ''conciliation'': Judge Kennedy may not be an ideologue, but he is a conservative who would never be mistaken for a Carter judge. The emerging budget agreement preserves the dramatic tax-rate reductions of the past six years. The defense budget and the Soviet-U.S. negotiations have not eliminated Reagan's dream of a strategic defense system.
Stockbrokers and store clerks alike plainly welcome signs of cooperation in Washington, and the principal beneficiary of that approval is likely to be the Republican nominee Reagan hopes will succeed him. That may be, in the end, the most effective way to ''lock in the revolution.''