SINCE THE COLLAPSE of the American-backed regimes in Vietnam, Laos and Cambodia, the United States has granted sanctuary to about half of the 300,000 refugees who have fled those countries. Now the White House, at the State Department's request, is considering the emergency admission of 15,000 more - people who are crowded in temporary refugee camps in Thailand and, in some cases, adrift on flimsy boats on the open sea and unable to find permission anywhere to come ashore. Israel took in a few the other day and other countries - notably France, Canada and Australia - have been lending a hand.

The 15,000 refugees that the State Department is immediately concerned with would seem to us to have the same claim on American compassion as their predecessors. But a White House decision to have the Attorney General admit them under his emergency "parole" power has not been forthcoming. One reason apparently has to do with sloppy handling by the bureaucracy of an admittedly complex issue with government-wide ramifications; HEW, for example, has been slow in its study of the health and welfare implications of admitting a new, large group of refugees. Another reason has to do with polital protocol: The President evidently is reluctant to force an argument on the question with Rep. Joshua Eilberg (D-Pa), chairman of the House immigration subcommittee, who has introduced legislation requiring among other things, special congressional approval for the emergency admission of refugees.

We can appreciate that the issue is complex. Still this is not a problem that lends itself to the business-as-usual play of American bureaucracy and politics. The refugees are out there in misery, in the refugee camps on the high seas. It is well enough established that they are people who, for the most part, left Indochina at least in part for considerations connected to the involvement and then the departure of the United States. Certainly the State Department thinks so. Mr. Eilberg, a compassionate man, surely will not make a legislative hostage out of people who are, to their already great distress, the Indochina war's pawns.

The evident distress of these people is one reason that the President should move swiftly to exercise his authority to let them in.A second reason, no less important for the long haul, is that these 15,000 refugees that the State Department feels have a special claim, through family connections or whatever, to sanctuary in the United States, are only a fraction of the estimated 80,000 Cambodians, Laotians and Vietnamese huddled in the camps in Thailand. The number is mounting rapidly; intelligence reports have suggested that Indochinese refugees may be pouring across the Thai Border at the rate of 1,500 a month another 500 are said to be fleeing each month by boat.

The United States can't begin to handle them all. This is why, for some time now, American diplomacy has been directed toward mobilizing a worldwide effort to deal with larger, longer-range problem of finding permanent refuge for this swelling tide of victims of the long, cruel Indochinese tragedy. American leadership is not likely to inspire others to concerted action, however, while this county is doing mothing about those 15,000 refugees in whose behalf the State Department is now acknowledging a particular American responsibility.