The big budget talks may be over, but the real budget battling has only begun.

Unless Congress is willing to accept the economic and political consequences of a $180 billion deficit for fiscal 1983, and even higher deficits for future years, it has no alternative but to keep trying to come up with the specific spending cuts and tax increases that eluded the White House and congressional negotiators in five weeks of secretive bargaining.

And it must do so quickly.

The deadline for a first congressional budget resolution, which would set spending and revenue targets for the 1983 fiscal year starting Oct. 1, is May 15, a deadline that now appears almost impossible.

Even more important, the Treasury Department estimates that Congress will have to approve a debt ceiling increase by late May, which is a deadline Congress will have no choice but to meet, because the government grinds to a halt when it lacks further power to borrow to meet its daily obligations.

The problem is that many lawmakers have indicated reluctance to vote for more debt without demonstrating to their constituents, and to financial markets, that real efforts are being made to reduce the annual deficits that contribute to the national debt, which now exceeds $1 trillion.

The purpose of the talks that broke down yesterday was to make it easier for Congress, which is institutionally ill-equipped to write a budget of its own, to make the difficult choices that are needed to reduce next year's probable deficit to something close to $100 billion, which is what congressional leaders are trying to achieve.

This meant, and still means, finding about $75 billion of deficit reductions from a budget that is expected to approach $800 billion for fiscal 1983. By contrast, Congress last year came up with about $40 billion in savings in what was regarded as a historic binge of budget-cutting.

The political appeal of bipartisan negotiations, with President Reagan and House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) standing by prepared to embrace the results, was that the talks provided a kind of election-year political cover to all the involved parties.

A compromise entailing unpopular actions, such as raising taxes or cutting Social Security benefits, would make a convenient political target for anyone who did not have a hand in the drafting. But, if the accord were drafted by both parties and ratified by Reagan and O'Neill, it would be a case of shared responsibility.

The negotiations were never seen as a total end run around the normal budget process, but rather as a way to oil the machinery of the process. That process will now begin without benefit of a prior agreement, starting with the budget committees of the two houses, as they mark up their versions of budget targets for next year.

If agreement can be reached quickly on spending cuts and tax increases, the deficit reductions could be tacked onto the debt ceiling legislation or put into so called "reconciliation" instructions to congressional committees, as was done last year.

Under this process, as the House and Senate pass their budget resolutions they instruct their committees to come up with the actual spending cuts and tax increases to meet their goals.

Or, in the absence of a packaging scheme, Congress could try to muddle through with separate tax and spending measures, possibly stretching out over the entire year, a situation that would invite Reagan to veto any bills that exceed his budget.

This could produce precisely the kind of partisan confrontation, congressional paralysis and deficits the negotiations were intended to avoid.