THOMAS B. REED, one of the most autocratic speakers of the House, once remarked that the best way to run the two-party system was "to have one party govern and the other party watch." That method will be on display today when the new House of Representatives convenes and adopts its rules. The 276 Democrats are likely to vote unanimously, or nearly so, for the package of rules changes that their leadership and caucus have endorsed. The 157 Republicans are likely to have about as much influence as the two vacancies.

In one respect that's too bad. Minority Leader John J. Rhodes (R-Ariz.), GOP conference chairman John B. Anderson (R-Ill.) and others have some sensible ideas, especially on improving committee procedures. They deserve a hearing. On the other hand, if one believes in party responsibility, setting the rules is one of the majority's prerogatives. And the Democrats' proposals are not the stuff of tyranny at all. Instead, they strike us as useful, though modest, attempts to improve the flow of work on the House floor. For instance, according to Rep. George E. Danielson (D-Calif.), nearly a third of last year's exhausting 149-day session was consumed by 942 roll calls. Some of today's changes should ease that burden a bit.

More important than what the Democrats do today, however, will be how long their party discipline and self-control last -- and how their dominance of the House will be used.The best way to cut the number of roll calls, for instance, is to bring fewer and better bills to the floor. President Carter's program is likely to be less demanding than last year; that should help. But House members and committees will also have to resist, more than they're naturally inclined to, the temptation to advance some bit of business to accommodate each constituent and lobbyist that comes around.

Changing the rules is no substitute for political selfdiscipline. Take the matter of trying to curb federal spending. During the annual budget debates, it has become routine for someone to propose an overall spending cut without specifying what programs or categories should be reduced. Obviously a vague, across-the-board cut can be a fraud or a cheap shot.But it's also easier to support than reductions explicitly affecting a program that one holds dear. After several years of struggling to beat down such amendments, the Budget Committee's Democrats have persuaded their colleagues to advance a rules change prohibiting them. If that is adopted today, budget-cutting motions henceforth will have to make clear where the ax will fall.

Now that may seem to be a step toward fiscal accountability. But maybe not. Perhaps the Democrats want to change the rules because they fear that they won't be able to ward off the budget buck-passing amendments as they go along. If they really had the political will to handle the budget responsibly, they wouldn't need this rule. If they don't have the gumption, the rule won't provide it; those who want to waffle on federal spending -- and the Democrats have no monopoly on this sort of thing -- will simply find other ways. That's just one aspect of the performance of the House majority (and the minority, as well) that the voters will be watching carefully in the months ahead.