Victory for Congress - and the President. BRINGING IN THE BUDGET

The deficit-busting budget package sent to President Reagan yesterday represents the single most significant achievement of the 100th Congress's otherwise lackluster first session. Not only is it designed to lop $36 billion from the current fiscal year's budget deficit, but it sets into motion a host of policies and programs that have occupied lawmakers' energies during the more than 2,000 hours the House and Senate have been in session this year.

The fitting conclusion to the contentious 1987 session came in the wee hours of Tuesday, when lawmakers put the finishing touches on a pair of budget bills.

At a little past 3:30 a.m., a bleary-eyed Senate following the House's lead, passed a $600 billion spending package - the biggest in history - and sent it to the White House for Mr. Reagan's signature. Just a few hours earlier, both chambers had passed a $17.6 billion parcel of taxes, benefit reductions, and other budget savings. Together, those actions were the last step in an unusually torturous budget process that dominated the congressional agenda during the last 12 months, and the last task to be performed before Congress' final adjournment for this year.

They also added up to a victory for the President and Republicans generally, who were able to win many concessions they sought from the Democrats while ceding comparatively little in return.

``The President won his poker game,'' sniffed House Appropriations Committee chairman Jamie Whitten (D) of Mississippi.

He was referring to Reagan's ability to force the Democrat-controlled Congress into assenting to an $8.1 million stopgap extension of aid to the Nicaraguan contra rebels, largely by promising to veto any spending bill that did not include funds to keep food and weapons flowing to the rebels.

Later, Republicans, once again backstopped by a veto pledge, managed to fend off Democratic efforts to enact the Fairness Doctrine into law by attaching it to the spending bill.

The doctrine, a Federal Communications Commission regulation until the agency stopped enforcing it in August, required broadcasters to provide time for opposing views on issues of public importance.

Earlier this year, the President vetoed a bill to write the doctrine into law.

Republicans argued that, by wrapping the doctrine into a bill that had to be passed to keep the government operating, Democrats were essentially trying to override the President's veto with a simple majority, rather than the constitutionally mandated two-thirds vote.

On such questions did the fate of the entire spending bill revolve. For lack of funds, the federal government was prepared to begin shutting down its operations yesterday if lawmakers and administration officials were unable to work out their differences. That threat, coupled with the distinctly unsavory prospect of spending the Christmas season on Capitol Hill haggling over such issues as medicare cost reimbursement, seemed to help quell the most fractious disputes.

Still unresolved is whether this legislation represents triumph or failure. For the current fiscal year, which began last Oct. 1, the total federal budget tops $1.1 trillion.

The budget deficit could hit $150 billion.

Yet, without any new action to tame the deficit, it would have topped $170 billion.