The United States seems destined to get its first balanced federal budget in 12 years, but it will not come easily -- or probably last long. Both the Senate and House of Representatives now have enacted no-deficit spending plans for the government for the first time since 1969.
But putting the budget in final acceptable form, and then sticking to it throughout the coming fiscal year, could prove troublesome.
Although cleared by both houses of Congress, the only certainty about the budget for fiscal year 1981 appears to be the overall, black-ink figures.
Precisely how the money will be divvied up within the budget remains much in doubt.
That is because the Senate and House adopted sharply different versions of the document. The Senate version ladles out $7.8 billion more money for the military than the House's and lops off correspondingly more funding from social programs.
The billion-dollar differences began to be hammered out this week by representatives from the two bodies.
Despite the sedate setting for their sessions, in a high-ceilinged room in the House's turn-of-the-century Cannon Office Building, the bargaining could be arduous.
Any efforts to reach a compromise by scaling down the extra dose of defense spending in the Senate's budget, enacted May 12, can be expected to meet special resistance from Senate Budget Committee chairman Ernest Hollings (D) of South Carolina.
Not only does Senator Hollings have a personal interest in defending the added military funding -- since he spearheaded its inclusion in the Senate budget -- but he has a desire to prove himself as a tough negotiator in his first budget parley since succeeding Edmund S. Muskie, the new Secretary of State, as chairman earlier this month.
Once a compromise is agreed, the next challenge is to keep federal spending at the budget's delicately balanced level somewhere between the $611.8 billion voted by the House and the $613.1 billion voted by the Senate.
That task may be made easier by enforcement "teeth," implanted in the budgetary process for the first time, requiring individual congressional committees to achieve specified amounts of savings in spending programs under their jurisdiction.
Other factors, however, could undo the budget balance.
"The fact is that even the most stringent budget is subject to change during the year," warns Rep. Barber Conable Jr. (R) of New York, a senior House conference. "The real plan is likely to be written by events, not by the planners. The budget restricts change, but does not prevent it. And what Congress has wrought can be unwrought."
Among the perils:
* Recessionary impact. A deep economic recession could slacken tax revenues while draining out more government money for unemployment compensation and food stamps. It also could increase demands on Congress to enact job-creating programs and other measures to stimulate the economy.
* Inflationary costs. Continued high inflation would trigger costly new rises in social security payments and federal retirement checks, which jump automatically with the consumer price index.
* Oil-import fee unpopularity. If mounting congressional opposition to the President's new $10 billion to $12 billion tax on oil imports results in its repeal, the new budget would suddenly plunge into deficit.
* Election pressures. Promises of campaign contributions and votes in this election year may prod Congress to heed the demands of various special-interest groups to increase federal spending benefiting them. Already the Senate has bowed to heavy lobbying from veterans and postal unions by adding to the budget