President Carter may find it more difficult than he expected to stave off an election year tax cut as part of his latest anti-inflation strategy.

Before Carter proposed his new budget Jan. 28, Congress seemed generally agreed that despite the coming campaign -- and widespread predictions of a recession -- cutting taxes now would do more harm than good.

Talks with both liberals and conservatives showed surprising unanimity: A broad-scale tax reduction might overstimulate the economy and could be taken by voters as a sign that Congress was abandoning the anti-inflation fight.

Most lawmakers then seemed visibly more worried about keeping down the size of the federal budget deficit -- a factor of far more concern to the electorate. The view was shared by senior legislators and influential junior members alike.

Now, less than two weeks after the president unveiled his new fiscal 1981 spending plan, there's been some slippage of that resolve, and congressional talk of a tax-cut has intensified:

Just last week, a joint House-Senate conference committee considering Carter's proposed crude-oil tax bill moved to earmark more than half its $227.3 billion in new revenues for general income-tax relief.

Although the move ultimately could prove to be only symbolic, it nevertheless represented a decided departure from the law makers' earlier mood. Administration lobbyists were fighting to water the provision down.

Backers of a spate of narrower-focus tax-cut plans -- from faster depreciation writeoffs for business to a new $3 billion tax break for charities -- began pushing anew for their own tax-cut proposals.

Their efforts are likely to heighten pressure for a broad-scale tax-cut bill. In most cases, these narrowers bills wouldn't stand much chance this year unless there is a larger tax bill to which they can be attached.

Republicans have begun stepping up their campaign for a broad-scale tax cut this year. Although their call is being dismissed in Washington as election-year campaign rhetoric, it could bolster tax-cut sentiment over time.

The modest but perceptible shift in congressional attitudes stems from a new realization about the impact of Carter's no-tax-cut proposal, brought home only after the new fiscal 1981 budget was unveiled:

Forgoing a tax cut means not only that there will be no reduction this year. It also means a $40 billion increase in the tax burdens of business and individuals this year. And that's something that may take the lawmakers time to swallow.

The tax boost will come from several factors -- the impact of inflation in pushing taxpayers into higher brackets, the scheduled rise next January of Social Security payroll taxes, and the crude-oil tax Congress is set to enact.

Although the president recommended against any tax cut this year, his budget showed that if Congress doesn't cut taxes it will push Americans' tax burden to 21.7 percent of the gross national product -- the highest since 1944.

Carter had promised earlier to trim this figure back.

Admittedly, the change among the lawmakers still is a slight one and doesn't yet represent any stampede toward a tax cut this year. The prevailing sentiment in Congress remains for holding the line.

But the shift points to a sober reality: For all the tough rhetoric, congressional feeling on the tax-cut issue is apt to be so volatile that the decision ultimately will depend almost entirely on Carter.

If the president stands firm in opposing broad-scale tax-reduction, it still appears likely that the tax-cut sentiment can be held in check. But if Carter opens the door even slightly, Congress probably will go whole-hog.

What is saving the administration now is that inflation is continuing to rage, while the recession hasn't yet taken hold -- so the electorate still is more concerned about the budget deficit than it is about the jobless rate.

For all the temptation the tax-cut notion may provide, the president's proposed red-ink figure still is $15.8 billion -- and many analysts believe it easily could swell to $30 billion or $40 billion before the year is over.

Also overlooked by some tax-cut advocates is that in avoiding tax-reduction as he did, Carter sought to compensate in his budget by allowing spending to rise more sharply than he would have otherwise -- both in the defense and domestic areas.

The president this year virtually abandoned the budget-slashing campaign he undertook in his fiscal 1980 budget. Spending for most major domestic programs was allowed to climb at least enough to keep pace with inflation.

And Carter has said he will go along with congressional efforts to ready antirecession job programs in case the unemployment rate begins to soar. Congress is putting the finishing touches on those bills now.

But the real rub is in boosting defense spending, which is likely to prove the biggest obstacle to pro-tax-cut legislators:

If the lawmakers want to see military outlays rise -- as most apparently do -- they simply cannot cut taxes this year and finance guns and butter both. They either must slash domestic spending programs or see the budget deficit balloon.

No doubt that will become apparent as Congress begins to grapple with these issues more seriously. But for now, Carter has some work to do if he is to keep Congress from atching tax-cut fever. The bug is in the air.