AS THE FIRST floor debates on the 1981 budget heat up in both houses of Congress, it is important to remember that they involve two very different disputes. One is substantive -- guns versus butter, or who gets what. The second concerns procedures and jurisdictions: the budget committees are trying to make Congress stick to the decisions it has already reached on the budget totals through the legislative year.

In a way, it is the second, less exciting argument that is the more important. Can the federal government discipline itself? Few Americans seem now to believe it really can.

The issue around which the fight is forming is called "reconciliation." This is the requirement that any individual act of Congress -- appropriation bills, new authorizations and so on -- follow the expenditure amounts permitted various parts of the government in the overall budget resolution.Budget committees in both houses are trying to get this requirement imposed early in the year, so that members of Congress won't be tempted to 1) vote for budget balance in May and 2) vote thereafter for every budget-breaking bill their consitituents might like between May and October.

There is some basis for this anxiety. Since the congressional budget process was established in 1974, the votes generally have been conservative on the overall totals, which were not binding, and then considerably more liberal on each sub-part. As a result, expenditures have always exceeded what was planned, and the final reckoning came too late in the year to matter.

The budget committees are on the right track. Devastating as the effect might be on some of the members' operating style, if Congress is to be even slightly coherent on budget matters, it needs to set its own goals -- and stick to them.