Talk about Reefer Madness.

The first issue to stir up the leaden oatmeal of college campus indignation in years is the news of the paraquat poisoning of marijuana.

From Fred Harris' freshman government class at the University of New Mexico to graduate biophysics seminars at M.I.T., the students are angry again. As one jaundiced assistant professor put it. "It's the only thing I've seen them protest in three years - outside of a low grade."

Students everywhere are outraged that "their government" financed the pesticide spraying of Mexican marijuana plants. It has turned into a melting pot (forgive the pun) issue among young people today, into which they've thrown a lot of anger, cynicism and a strong dose of irony.

The irony is simply this: The government that failed over many decades to convince the public that marijuana is dangerousfinally has helped to make it dangerous.

In 1975, the Nixon administration gave Mexico $40 million to buy planes and train people to spray herbicides on poppy fields in order to kill off a major supply of heroin. On their own initiative, the Mexicans went on to more fertile fields and sprayed marijuana with the deadly chemical paraquat.

The idea was that paraquat would kill off the plants, the way it helped defoliate Vietnam. But each season, the enterprising Mexican farmers harvest the stuff before it dies, and ship it north.

Since about 50 to 60 percent of the pot smoked in this country comes from Mexico, it is assumed that for the past two or three years, a large number of the 15 million regular marijuana smokers have inhaled a substance that has a slow, cumulative effect on their lungs. Is there any wonder why the Bumper Sticker of the Moment in California reads: "Buy Colombian"?

The question is now whether the Carter administration which has taken a stance in favor of decriminalization of marijuana, feels any responsibility about the Mexican program. And the answer is mixed.

On March 12, HEW did issue a warning about paraquat to "consumers." But on March 28, the spraying was begun on the spring crop, with our money.

Dr. Peter Bourne, the president's special assistant on health, states the government's position this way: "People are asking the federal government to protect them in a patently illegal act. If it's against the law, the responsibility of the government to protect its quality doesn't exist."

But no one is actually asking the government to roll up 12 neat joints and put them in an FDA-inspected cellophane package. They are complaining that the government is poisoning the stuff.

Bourne makes a second analogy, saying that "the whole area is filled with ambiguity; it gets into questions like 'Should we offer health care to someone who gets into an accident going over 65 miles an hour?'" But, should we, on the other hand, give government grants to manufacture a brake system that fails at 65 miles an hour?

The National Organization for the Reform of Marijuana Laws (NORML) has filed a suit aginst the government, and a hearing is scheduled for April 26, although it may be postponed again. In the meantime, the people doing a boffo biz are the ones running test labs on all the vials of marijuana being sent in by all the worried users.

For once, NORML is raising the health issues of smoking marijuana. As George Franham, the assistant director, put it: "This is total role-reversal."

But the fact is that there are currently 45 million Americans who have smoked marijuana. Right now nine states - inhabited by a third of the population - have decriminalized it. Furthermore, in the latest Gallup polls, 70 percent of the population of those under 30 and those with a college education are in favor of decriminalizing it.

Marijuana has become a gray area of the law and an issue of debate on and off the college campus. But who is in favor of poisoning marijuana smokers? This paraquat punishment just doesn't fit the "crime."