The scales of justice shouldn't be used as a political stump

Over the next few months some radical anticrime legislation and criminal-justice reform will either succeed or fail in Congress. With one eye on the ballot box in this election year and another on the Supreme Court, which could wind up its term later this month with some precedent-setting decisions, lawmakers will be prodded into action - or inaction - on this front.

Certainly there's nothing wrong with legislators testing political winds and responding to public clamor - as long as they also heed constitutional principles of equality, fairness, and protection of individual rights.

As might be expected, the Republicans - led by President Reagan - are calling once again for ''taking the handcuffs off law enforcement.'' Administration proposals include a crackdown on drug trafficking, reforms in bail and sentencing, restructuring the insanity defense, limiting the exclusionary rule, and reinstating the death penalty for certain federal crimes.

Democrats, on the other hand, particularly those of a liberal stripe, are less enthusiastic about tightening the reins in the criminal-justice area. They warn that this must not be done at the expense of individual rights.

Some measures - to better protect children against pornography and sexual abuse as well as to beef up the state and federal apparatus for finding missing youngsters - have already passed with strong bipartisan support. These are to the good.

Other measures that have considerable support from both parties are still under consideration. These mandate stiffer penalties for trafficking narcotics as well as federal coordination of drug-related enforcement. They deserve careful consideration, free of political grandstanding.

Among the more controversial measures that are being heatedly argued:

* Raising the drinking age nationwide to 21. One bill under consideration would levy a federal fine of up to $5,000 on anyone who sells liquor to a person under 21. This restriction would not go into effect for two years, allowing states time to bring their own laws into compliance with federal standards. Another measure would provide federal fiscal incentives to states that raise the drinking age to 21. (More than 20 states already impose this limit.)

While legal efforts to restrict the sale of alcohol and its consumption by youth are to be applauded, these moves won't be effective unless they are accompanied by parental and community leadership in changing attitudes about drunken driving - and drinking in general. Politicking often does not help in arriving at solutions.

* The death penalty. Regardless of whether Congress takes action or not, capital punishment will likely remain a matter for the courts. Under present law it is used sparingly. Studies vary on whether the penalty actually deters crime. Some surveys indicate, however, that under the present system racial minorities and the poor are more apt than other defendants to receive a death sentence. Guidelines that aim at ''equal justice'' in this area have been helpful. But the basic question lingers: Is legally mandated execution - for whatever reason - consistent with a political philosophy that embraces human dignity and prides itself on tempering principle with compassion? If not, capital punishment isn't a viable option for checking crime in this country.

* The insanity plea. In seeking to limit or outlaw the insanity defense, the Justice Department cites the disposition of the case of John W. Hinckley, who shot and wounded President Reagan, as ''a stark example of abuse.'' It backs bills that would sharply limit the use of this plea as a defense, restrict the importance of psychiatric testimony, and place the burden of proof about the question of insanity on the defense rather than on the prosecution. Sponsors cite dramatic examples of defendants acquitted by reason of insanity who are set free and then repeat violent crime.

If we are to change the insanity plea, it should not be in the heat of emotion - or on the basis of selected heinous offenses. There is little evidence that existing federal laws are ineffective. And states are already starting to address the issues of plea and expert testimony. Reform, again, must be thoughtful, principled, and compassionate - not spawned by emotion-charged rhetoric.

* The exclusionary rule. The courts as well as Congress may be on the verge of what President Reagan considers the centerpiece of his campaign to ''take the handcuffs off law enforcement'' by modifying the rights of the accused. The administration is calling for reform of the exclusionary rule (under which evidence improperly or unlawfully obtained by police is excluded from court consideration) and of other criminal-justice procedures. The administration argues that victims' rights have too long been subordinated to protections for criminal defendants. The implication is that there is a direct trade-off. There is not, however. A democratic society, in the long run, is not endangered by upholding constitutional rights of all its citizens - even those who are outlaws. On the contrary, it is strengthened.

An old campaign slogan of incumbents is: ''Don't let them take it away!'' This is also an appropriate admonition to those well-intentioned but unwise people who want to tamper with constitutional protections for the individual in the name of reform.