Washington is enduring its second winter of discontent. Just as a year ago, hard budget choices are depressing the capital's mood. But alongside the budget wrestlings is a revival of confidence in the basic balance of power here - between conservative and liberal, White House and Congress, Democrat and Republican.
''Exactlym the time the White House last felt beset was exactlym this time last year,'' says Stephen Hess, a Brookings Institution expert on White House and Washington press affairs.
''Last year, press leaks from late December to mid-January culminated in lie detector tests at the Pentagon. The odd thing is, Reagan is responding without even a memory of one-year's standing. We are in that pre-budget-message blues phase.'' Such White House exasperation with budget leaks is familiar back to President Truman's days, Mr. Hess says.
Concerning budget matters, the White House has begun to show modest signs that President Reagan hears the clamor over deficits. Defense Secretary Caspar W. Weinberger now says $8 billion could be trimmed from the previously sacrosanct defense budget for fiscal '84. This is not enough to satisfy critics, although it may help Reagan look less stubborn about his priorities.
A survey by the Americans for Democratic Action showed Congress in the last session snapping back into its familiar liberal-conservative, regional alignments. ADA analysis found Democrats more liberal than Republicans by a 3 -to-1 margin - the average margin for the past decade. The implication, apparently, is that the Reagan revolution has apparently lapsed so far as any sharp gain in the conservative voting bloc in Congress is concerned.
''Washington is familiar in its alignments,'' says Thomas Mann, executive director of the American Political Science Association, and an authority on congressional affairs. ''But it's different in its preoccupation with fiscal issues.''
''This fiscalization of American politics - focusing on the budget, defense, recovery, deficits - is frustrating to politicians,'' Mr. Mann says. ''It means less and less of traditional politics. Previously, we had seen the peripatetic congressman in Washington, pursuing his own interests and bills. Fiscal issues have suppressed this tendency.''
One concrete result from this change: a sharp drop in the number of laws passed. Some 613 laws were passed in the 96th Congress in President Carter's last years, but the 97th under Reagan passed only about 400 new laws.
''What's different now is that everyone agrees what the problem is, though they may not agree the President has the answers,'' Mann says. ''The focus of Congress has narrowed. The individual congressmen are no longer running off with pet legislation of their own.''
A stronger Congress faces Reagan in 1983. ''The time when Reagan could get things he wanted at first run are past,'' says Robert C. Brown, executive director of the Tax Foundation, a fiscal watchdog group. ''I see some hope in the Congress getting together and talking about the seriousness of this thing. Talking about a freeze (on federal spending) is a helpful sign, though it's not clear a freeze itself is desirable.''
A new assertion of congressional leadership suggests a more equal division of power in Washington between the White House and Congress. This reassures some Washington observers that Congress may compensate for possible flaws in the White House formula for recovery.
''There's a lot we don't know yet about Reagan's budget,'' Mr. Brown says. ''The fear of the unknown is hard to deal with. The mood is one of uneasiness.
''There's a feeling the White House may be underestimating resources and overestimating expenditures - the reverse of what we had last year. There's a feeling they're doing it to force the President into accepting potential tax increases.''
While absolute levels of liberalism or conservatism in Congress cannot be measured year to year, the pattern of alignments can be tracked. The evidence shows ''an incredibly stable pattern of alignments, remarkably persistent over time,'' says Mann of Congress's evolution in the Reagan era. In 1981, he says, Reagan's congressional victories occurred ''at the margins'' - with swing moderate and conservative Democratic votes that began to move the other way in 1982.
But while the Republicans have suffered setbacks in the last election and in recent opinion surveys, not all evidence runs against them.
The public's approval of the Republicans' job in Congress (44 percent approve , 41 percent disapprove) is not far off the Democrats' rating (47 percent approve, 40 percent disapprove), according to a Penn & Schoen survey in December.
Even more interesting, voters split evenly (44 percent Democratic, 43 percent Republican) when asked whether they favor ''Democratic proposals for the budget, which call for more social spending, delaying the tax cuts, and reducing defense spending, or Republican proposals, which call for less social spending, keeping the tax cut, and increasing defense spending.''