YEARS OF hard work are at stake on the House floor today as final consideration is given to the Simpson-Mazzoli immigration reform bill. The legislation is intended to address the difficult and long-simmering problem of illegal immigration and to revise and clarify national policy toward legal immigrants and refugees. The measure is badly needed and should be passed.

The bill that the House will consider has been amended at every stage of the legislative process. Competing interest groups have adjusted; everyone has accepted less than 100 percent in order to get passage. There may be more amendments today because provisions, such as amnesty for illegal aliens and a special program for temporary farm workers, remain controversial. Five hours have been set aside for debate, and these and other issues can be considered by the full House.

But a small group of legislators who oppose the bill want more. They have introduced some 200 dilatory amendments and have threatened to ask for roll calls on each of them in an effort to prevent a vote on the bill. Because the time spent actually calling the roll does not count against the five-hour time limit, repeated delaying votes could take many days, which Congress does not have at this point. What is needed is a tough stand by the leaders of the House.

There is plenty of time for all factions to be heard and for members to review and resolve matters still in conflict. But threats and bluffs should not cripple the legislative process. Let the full House work its will.