The House is about to open floor debate on a measure crucial to the welfare of our nation. The massive illicit drug traffic can be stopped only by the direct involvement of our Armed Forces. This is what Congress must authorize now.

The General Accounting Office recently reported that federal agencies seize only 16 percent of the marijuana and less than 10 percent of the heroin and cocaine that comes into the country each year. The Customs Service says it intercepts only one out of every 100 planes flying cocaine and heroin into the country. There were 18,000 such flights in 1983.

But Customs Commissioner William Von Raab offers little hope. He says he doesn't "like statistics. I don't know what is served by using them." Small surprise. "For those who thought Customs was in any way guarding our borders," he reported after two years as commissioner, "we weren't."

How can it? The head of the Drug Enforcement Administration said recently that to curtail the flow of drugs effectively, he'd need 40,000 agents. In fact, he has only 1,900 worldwide.

The Coast Guard has no more than 10 boats patrolling the entire southeastern coast and Gulf of Mexico, the principal channel through which the bulk of illegal cocaine and marijuana enters our territory. Closer to home, in 1984 the Coast guard intercepted only two boats in the waters off New York.

There are no radar installations designed to detect drug flights over our southern coast. The DEA has only eight planes with sufficient overtake speed to police the border from Key West to San Diego. Our Border Patrol has no look-down, low-altitude radar, only a few interceptor jets with tracking radar, and only a small force of large, fast helicopters needed to transport agents to landing sites when suspect aircraft are forced to land.

The illegal narcotics trade is a $110 billion annual business, but the entire federal drug abuse budget totals only $1.5 billion. Only about two-thirds of this figure is committed to law enforcement programs, including prosecution, prisons and Internal Revenue Service auditors.

You can't win a war without weapons. Until the weapons are committed, the drug invaders will have a virtual free pass across our borders. That's why it's time to commit our armed forces to help in the battle against drug smugglers. The federal Posse Comitatus Act places significant constraints on military involvement in drug interdiction. Clearly prohibited are "interdiction of a vehicle, vessel, aircraft or other similar activity, and the use of military personnel for surveillance or pursuit of individuals."

The danger in such constraints was apparent on July 17, 1983. On that day the USS Kidd, a naval vessel with a six-man Coast Guard unit aboard, was on patrol in our southern territorial waters when it encountered a suspect ship flying a foreign flag. The ship was stopped, but refused boarding. The Kidd learned the ship was not registered in the country it claimed and, therefore, was a stateless ship that could be legally boarded, but only by the Coast Guard. Fearing its intervention would violate the Posse Comitatus Act, the Navy sought instruction from the Department of Defense as it trailed the vessel. Eventually, a Coast Guard flag was raised and the Kidd became a Coast Guard vessel. When its crew was finally allowed to board the pirate ship, a cache of drugs was seized. Though necessary, this stretching of the law illustrates the urgent need to revise the Posse Comitatus Act.

Rep. Charles Bennett (D.-Fla.) has introduced an amendment authorizing the direct involvement of the Armed Forces in the interdiction of illegal drug smuggling outside the land areas of the United States when requested by the head of a federal drug enforcement agency. The Bennett amendment, cosponsored by Rep. Charles Rangel (D-N.Y.), the chairman of the House Select Committee on Narcotics Abuse and Control, will resolve the legal ambiguities that led to the USS Kidd incident.

It has been suggested that the assignment of the military to the role of interdicting drug trafficking would divert crucial personnel and resources from the primary mission of the Armed Forces and, potentially, have a negative impact on our nation's defense preparedness. Gen. Paul F. Gorman, recently retired as commanding officer of the Army's Southern Command, with headquarters in Panama, told a Senate Committee on June 4 that, on the contrary, such a role for the military would improve training and preparedness. Furthermore, he directly linked the drug traffic to the funding of weapons for terrorists in Central America. In the course of questioning by Sen. Alfonse D'Amato (R.-N.Y.), Gen. Gorman endorsed the Bennett amendment.

We have witnessed the largest military buildup in our nation's history, with over a trillion dollars being spent on defense in the past four years. Our Navy and Air Force presently have a major presence in the Caribbean and along our nation's coastline and borders. They should be assigned, at the request of civilian law enforcement authorities, to track down and intercept drug smugglers. Americans have great respect for the ability of our Armed Forces to ensure their safety and security. If given the responsibility to interdict international narcotic trafficking, the military will succeed. It should also be remembered that the military's role will be limited to points outside the land areas of the United States, where the civilian law enforcement agencies, acting alone, have only marginal effectiveness.

The United States remains under siege, confronted by a tidal wave of drugs. Let's use the weapons at hand. Let's commit te military to the defense of the nation by deploying our Armed Forces along our borders and on the high seas to interdict drugs. The writer is mayor of New York City.