The usually cheerful Rep. Richard Cheney was playing Scrooge as Christmas neared, a sign of deep trouble for the Republican Party stemming from the administration's post-election estimates of massive budget deficits.

Those estimates, churned out by David Stockman's Office of Management and Budget and approved by the White House, base long-range pessimism on short-term decline (in 1984's last two quarters). The OMB forecasting model, remarkably inaccurate in the past, precludes serious deficit reduction resulting from economic growth. Therein lies a foreboding that ruined the holiday season for Cheney and other traditional Republicans.

Cheney, chairman of the House Republican Policy Committee, was displaying the same long face in sect strategy sessions with administration officials that he showed to reporters. He argued that by not making deeper cuts in the defense budget, President Reagan had threatened his entire second term. What's more, Cheney wants to hold down Social Security payments and warns that insufficient budget cuts could lead to higher taxes -- both acts breaking Ronald Reagan's campaign pledges.

Cheney is not alone. He represents the overwhelming consensus among Republicans in Congress. Another GOP House leader, Rep. Jack Kemp, is a voice in the wilderness arguing that only economic growth can reduce the deficit.

Thus, just as the Republicans are poised to achieve majority status, they are in danger of resuming the austerity posture from which they futilely battled the New Deal. Only the president in his Inaugural and State of the Union speeches next month can change the mood.

Such politically self-destructive austerity is the byuct of the OMB model. It projects little decline in unemploymnt -- a direct cause of high federal spending -- resulting from economic growth. Nor does it anticipate reduced expenditures because of lower inflation.

In contrast, the Congressional Budget Office model, while predicting an even gloomier economy, does concede a closer link between growth and budget deficits. Using the CBO model, Kemp's office reports that a single percentage point in economic growth would yield a $105 billion deficit reduction within three years.

That suggests that the answer to Stockman's deficit crisis lies not in austerity but in two areas that Reagan's senior aides privately give top priority: tax reform and monetary reform. It is here that Capitol Hill Republicans lose interest.

Cheney's attitude toward the Treasury's tax reform ranges from unenthusiastic to hostile. Few voices in Republican cloakrooms assert that an amended version would promote growth, an argument that has yet to be pressed by the White House.

There is even less interest by Republican lawmakers in connecting monetary policy with budget deficits. Most simply do not grasp that this year's abrupt application of brakes to the economy by the Federal Reserve Board retarded growth and enlarged deficits.

When Kemp brings up monetary policy in meetings on the Hill, eyes roll in exasperation. His tax reforms attract more attention from Democrats. It will take Ronald Reagan to deflect Republicans from inflicting austerity on the nation. He has less than a month to begin.