President Reagan has recommended adding 1,200 agents to federal law-enforcement to battle the growth of organized crime. That should help, but much of the real weakness in reaching that goal effectively lies behind legal shenanigans and courtroom benches.

Arrested criminals stay out of jail for long periods while trials are postponed, and if trials result in convictions, attorneys file appeals or crawl through other loopholes in efforts to keep their clients at liberty.

But those who have the real power and authority to punish major offenders are the judges. Many justices (the word is sometimes a mockery) impose lenient sentences that have little or no effect in deterring offenders, including those who have not yet been caught. Some judges even sentence convicted defendants to suspended sentences, which means no imprisonment at all.

Years ago in New York City, there was a rash of offenses involving the passing of counterfeit money in retail stores. Would-be customers made $1 or $2 purchases with phony $20 bills. In many cases the bills were detected by clerks who notified police. The police in turn called the Secret Service, which enforces counterfeiting laws, and in virtually all cases, the suspects carried other paper money, all genuine, and argued that they themselves were innocent victims of the counterfeits.

In Secret Service parlance, most of them were known as "one-note passers." They worked in pairs. One held a quantity of counterfeits and waited nearby or outside the store while his confederate took only one bill to make the purchase. If the fraud was discovered and the buyer was questioned, it seemed reasonable to believe that he had not known the bill was a fake. And the confederate with the bankroll could walk away.

Some passers were taken before the U.S. attorney in New York, who refused prosecution on the grounds that no jury would convict such defendants, since innocent acceptance of a counterfeit might happen to anyone.

Secret Service officials, in conferences with the U.S. attorney, asked that prosecutions be instituted in the cases of those one-note passers who had criminal records and who had been convicted of other crimes. The U.S. attorney finally agreed. In some cases, the passers then pleaded guilty; in others, conviction resulted.

The Secret Service and the U.S. attorney described the one-note modus operandi to judges in the hope that substantial sentences might help to deter the practice. The judges were cooperative, and instead of imposing suspended sentences, or sentences of six months or a year, they began to sentence convicted offenders to longer terms.

Faster than a speeding bullet the word flashed through the underworld, and it was not long before the heyday of the one- note passer became his Mayday.

The point here is that operators in the underworld, no matter what their specialties, keep close track of the fates of their kind who are haled before the bars of justice to be punished for serious violations of our laws. If the penalties are severe, then the chances are good that the offenses will dwindle.

Law officers carry guns and willingly risk their lives to put vicious criminals out of business. Judges are law officers, too, and although they do not carry firearms, they wield powerful weapons of punishment that could enable the aims of their armed colleagues to succeed -- or fail.