THE TERMS of the continuing resolution,

passed by Congress in its pre-holiday rush, represent a large change in the nation's definition of federal responsibility and in the role of Congress in contriving that definition. The cuts in domestic spending made by the measure are real and big-- bigger than you probably would have thought if you had been following the budget process piecemeal. Remember that roughly four-fifths of the budget is off-limits because it's defense, Social Security or another untouchable, like the FBI. The vulnerable remainder would have been in the range of $155 billion under the Carter budget for this year. Spending in this part of the budget has been cut by perhaps a third--one of the curiosities of this whole process is that no one is quite sure.

The president proposed his first round of budget cuts last March. During the summer, Congress gave him most of what he wanted. In September, however, he asked for still more--a further cut of at least 12 percent in most domestic programs. The Congress balked. By Thanksgiving, it had agreed on a measure that included less than a fourth of the new savings the president sought. The president vetoed the bill and shut down much of the government. Congress hastily passed a short-term spending measure and negotiations began again.

This time the White House did better. It lined up Republican leaders in both Houses, hammered out a detailed agreement acceptable to the president, made a few concessions to moderate Republicans and southern Democrats in the House and rammed the compromise through both houses in time to get Congress home for Christmas.

The final bargaining involved about $4 billion. The full reduction in domestic spending implied by the resolution is, however, many times that amount. The agreement reached by the Office of Management and Budget and the Republican leadership set the base level for each individual program at the lowest amount previously voted by either the House or Senate or--if the full Senate had not acted-- recommended by the Senate Appropriations Committee. Against this base--which in some instances already included the 12 percent cut asked for in September--an additional reduction, averaging 4 percent, is to be applied by the administration. The president thus obtained an overall cut in domestic spending that not only met, but substantially exceeded, his March request.

The lost $50 billion bought many government services--everything from public housing and help for elderly shut-ins to mine inspections and basic scientific research. Some programs, in particular those run by state and local governments, will have to be cut back even more sharply than the resolution implies in order to make up for overspending in the months before the final cuts were imposed.

It will be many months before anyone knows exactly what changes have been made in the many services the federal government provided or supported. Meanwhile, enormous disruption and inefficiency is taking place at all levels of government as agencies struggle to reduce their staffs, reshuffle the remaining employees and figure out what can still be done. When Congress returns from its holiday, it may, as Senate Majority Leader Howard Baker has suggested, want to reconsider some of what it has done to government services. It may also want to reconsider its recent method of participating in the making of federal policy.