Act on aliens

Congress - and that largely means the US House of Representatives - deserves the plaudits of all Americans for at last voting to curb illegal immigration into the United States.

Many legislative hurdles remain. It is crucial that lawmakers take advantage of the current momentum and move forward as quickly as possible to reconcile the Senate and House versions of the Simpson-Mazzoli immigration bill so that a final act can be signed into law by President Reagan this session.

What is remarkable is that the measure passed the House at all this presidential election year, if only by a mere five votes (216-211). Many observers had not thought Congress would muster the courage at this time, given the sharp opposition from groups as divergent as big labor, Hispanics, civil libertarians, and the business community.

The closeness of the vote underscores the concerns that lawmakers have about enacting any new immigration law. The concerns mainly revolve, as they should, around questions of equity - regarding Hispanics, other immigrant groups who might be affected, and employers. Yet, clearly the majority of lawmakers recognize that something has to be done to curb the wholesale violations of US immigration laws now taking place - that the current drift, in other words, can no longer be tolerated.

The House and Senate versions of the legislation contain many differences, although they are both in agreement on their general goals.

We continue to support those broader objectives: namely, provide penalties for employers who knowingly hire illegal aliens; grant amnesty for aliens who have resided in the US over a long period of time; and allow for a flow of ''guest workers'' into the US to perform needed seasonal agricultural work.

At the same time, a number of aspects of the legislation remain troubling and need especially sensitive handling by House and Senate conferees:

* Verification. The House version seems preferable to the Senate version, which was passed last year. The House bill would eventually establish a telephone check-in system whereby employers could verify the validity of a social security card. The Senate, by contrast, would provide some form of secure identification card system.

* Guest workers. Estimates on the numbers of temporary workers that could enter the US under the House bill range up to 300,000 or more workers annually, compared with the current level of 20,000 annually. Such numbers, to say the least, are generous. But any guest-worker program of that magnitude needs to be carefully defined and closely regulated to prevent the type of job-related abuses against farm workers that occurred during the period of the bracero program back in the 1950s.

* Amnesty. The House version makes more sense than the Senate version on amnesty. The House would offer temporary legal status to all aliens who had established residency in the US since Jan. 1, 1982. The Senate bill provides permanent residency for persons residing in the US before 1977 and temporary residency to persons establishing residency from 1977 through 1979. Why not, as the House measure does, clear the desks on the issue once and for all?

In addition, Simpson-Mazzoli would impose curbs on the numbers of relatives who could be legally brought into the US by all ethnic groups.

Finally, while it is essential for lawmakers to restrict illegal immigration, the measure must not be allowed to be used to generate a new xenophobic campaign against immigrants in general.

The United States has always derived much of its vitality and vision from the idealism and cultural infusion of its newcomers.