ISLIP, N.Y. -- Scavenging gulls, living easily off the fat of the wasteland, hover above bulldozers piling garbage in the municipal dump. The 84-acre site is about 1,000 yards across, with a chasm of excavated earth as deep as a canyon. An American flag waves over the scale station where multi-ton trucks stop to have their loads weighed. If the world's most famous garbage must be dumped somewhere, here is the somewhere.

The pick of the litter -- 3,000 well-baled tons -- remains on a barge at Gravesend Bay in New York harbor, an attraction that draws tourist boats on the Statue of Liberty run. Islip, a south-shore Long Island town that now ranks with Love Canal and Times Beach as synonyms for unmanaged waste, is ready to take back what it sent on a Caribbean cruise more than 80 days ago.

But the town, with reason, resents being dumped on. Less than half of the barged garbage is Islip's. Most is from New York City or neighboring Nassau County.

Frank Jones, the Republican town supervisor, sums up the local politics of waste by calling Islip ''the Paul Revere of garbage.''

The warning is about an enemy few care to face and fewer still see as a threat. The Institute of Local Self Reliance in Washington estimates that in three years landfills in more than half of U.S. cities will reach capacity. Islip dispatched its debris to sea because the state legislature ruled that Long Island is running out of space. Burying garbage is a disposal method that has not advanced technologically since Greeks two centuries before Aristotle created a city-state dump outside the walls of Athens. Islip has been a dumping ground for the garbage of New York City, the nation's trash-producing capital, where citizens annually discard nine times their weight in refuse.

One reason America the Beautiful is becoming America the Trashy is the public's addiction to convenience. Recycling, like energy conservation, demands personal and institutional effort. The potentials for recycling are large for such ordinary throwaways as aluminum, paper and glass. Aluminum, first introduced to hold beverages in 1963, was used for 66 billion cans in 1985. The 1987 report of the Worldwatch Institute states that the metal ''can be recycled almost indefinitely.'' Most cans, part of the 90 percent of America's refuse that is buried, are used once.

Instead of being dumped on as irresponsible, Islip, as a matter of record, has kept its garbage cool, calm and well-collected. Section 21-2.1 of the town code requires that citizens separate recyclables from all other solid wastes. Detailed instructions are circulated on the art of enlightened discarding. During May and June, for example, in the towns of Seaview and Ocean Bay Park, nonrecyclables are collected Monday and Thursday, with Wednesday for recyclables. The latter include newspapers, corrugated boxes, glass bottles and jars, metal cans, plastic soda or milk containers.

The convenience issue occurs when household garbage producers refuse to do the separating that makes recycling possible. Except for those with a civic scruple or two, Americans are discarders of garbage, not separaters. Mix the coffee grinds, beer cans and newspapers, haul the heap to the curb, tip the trash collectors at Christmas, and that's it.

Except it isn't. The costs of not separating and recycling are rising higher than the trash piles. Six years ago, Minneapolis buried a ton of garbage for $5. Now it's $30. Philadelphia went from $20 to $90 a ton. Cynthia Pollock of Worldwatch writes that ''solid waste management is a large and growing share of city budgets. Yet evaluating alternative management practices is frequently left to the system's critics. The purchase-consume-dispose mentality is so well rooted in public attitudes that even proposals to shift from one disposal site to another -- for example, from a landfill to a waste-to-energy plant -- are touted as radical.''

Islip's congressman, Rep. Tom Downey, a progressive Democrat, recently introduced a bill proposing ''a national economic commission'' that would ''try to sort'' some of the ''economic problems.'' He should have been braver: Why not a national garbage commission to sort the nation's trash? Anyone running for president would be appointed to it automatically, with the expectation that politicians worthy of their spoils ought to have a plan for Hefty Bag spoils.

An irreverent question poses itself: Who is more able than the current crowd of presidential candidates in advancing the art of recycling trash? Any candidate stewing about how to break out of the anonymous pack has a sure claim on the front page of every U.S. newspaper: climb atop the Islip dump and announce a solution to America's garbage problem. If they want to clean up the mess, start here.