A conservative fiscal mood that has swept through the nation prevailed in the US Senate Wednesday as it passed a constitutional amendment to balance the federal budget.
Even as the federal government mounts up the highest deficits in history, the upper chamber by a 69-to-31 vote offered a promise that if Congress cannot stem the tide of red ink now, it will do so in the future.
The move, the first step toward amending the Constitution, puts new pressure on the House, where supporters have gathered most of the signatures for a discharge petition to force the amendment to a vote.
Critics of the amendment, led by Sen. Alan Cranston (D) of California, told the Senate it would ''hog-tie'' the government, that it was ''government by slogan,'' and an ''insult to the Constitution and an embarrassment to Congress.''
But in the end, Sen. Strom Thurmond (R) of South Carolina, who has been prodding colleagues to balance the budget for much of his 28-year tenure, and fellow conservative Sen. Orrin G. Hatch (R) of Utah held the required two-thirds majority.
Their victory, widely predicted, was a measure of election-year pressures, since few issues have more public support than balancing the budget. Polls have shown that as many as 90 percent of Americans favor it.
However, a balanced budget remains an elusive goal, even if the the House follows suit and approves the amendment. The measure must then go to state legislatures, where even some supporters doubt that there is enough backing to win the necessary 38 approvals.
Also, as passed by the Senate, the amendment would make it harder, but still possible, to vote in an unbalanced budget. It would require a two-thirds majority of both Houses to approve a deficit, except in war. And a last-minute revision would require a similar supermajority to raise the US debt ceiling.
The amendment would also limit revenue increases to the rate of national income growth, unless Congress takes a specific vote to raise taxes.
The balanced-budget move is only the latest in the current congressional struggle to control deficits. For more than a year Congress has focused almost exclusively on regaining control of government spending and tax policy. And it seemed no closer to victory as the balanced budget amendment squeaked by with two votes to spare on the Senate floor.
At the same time:
* A proposed $98.9 billion revenue raising bill, which had raced through the Senate, bogged down. The taxes, called for in the 1983 budget, would be required to keep the deficit from soaring even higher, say supporters.
* House members passed a budget-busting plan that would give federal workers on pensions their full cost-of-living raises. The House rejected the 4 percent cap outlined by the 1983 budget passed by Congress in June.
* Democrats are forcing the House to vote separately on a series of spending-cut proposals, requiring election-bound members to take unpopular stands. The result could be more budget-busting.
However, the biggest battle will probably center on the giant tax bill.
That bill would raise revenue by a variety of measures, including closing loopholes and tax preferences for corporations, doubling the federal cigarette tax, raising the tax on long-distance telephone calls, and requiring a 10 percent withholding tax on most interest and dividends. It would also reduce business lunch deductions to 50 percent.
Until recently the measure faced low-keyed criticism, in part because of the legislative maneuvering. Not only was the measure produced by Republicans meeting largely in private, but it effectively bypassed House committee consideration altogether when the House voted to send the bill directly to a House-Senate conference.
But critics are beginning to emerge out of their collective shock. A group of 60 conservative Republicans, led by Rep. Jack F. Kemp (R) of New York, have launched a campaign to delay final vote until Congress agrees to make more spending cuts. Mr. Kemp said earlier this week that he hopes to hold up action until election time, when the ''climate'' would defeat the tax increases.