WITH THE POSSIBLE exception of Attorney General Edwin Meese III, New York City Mayor Edward I. Koch more than any other American politician has openly advocated tougher penalties for violent crime. On this issue, Democrat Koch falls for the unconvincing Neo-Con attacks on the criminal justice system.

However debatable the issues may seem, what could be more disheartening than a Democrat who sides with the advocates of capital punishment with the argument that, "It is by exacting the highest penalty for the taking of human life that we affirm the highest value of human life"?

Presumably the oh-so-self-effacing Koch does not pretend to philosophical consistency. In Koch's rhetoric on crime it is difficult to find any inner moral conviction to support his demand for vengeance.

We need not look far for the index to his rhetoric. Koch has long been far more motivated by the chaos of public opinion on capital punishment and the ravings of sensationalistic New York newspapers than by some demonstrable ethical belief.

What else would explain the multitude of self-contradictory statements he made during last spring's Goetz case? Immediately after the incident--in which a New York citizen shot four Black youths on a subway in "self-defense"--Koch asked New Yorkers not to emulate Goetz's vigilantism. But when the press and public opinion swayed first in favor of Goetz and then against his hypothetical heroism, Koch swayed with them.

IN THIS CONTEXT, it is difficult to respect the purported intellectual content of Koch's writings on crime. Koch wrote for The New Republic and more recently contributed to Policy Review a slavishly favorable review of Harvard professors James Q. Wilson and Richard J. Herrnstein's Crime and Human Nature.

In the former article, Koch relies on the hackneyed deterrence argument--the unproven assertion that unwavering and well-publicized punishment for homicide will reduce its incidence. Though Koch's standpoint is that of the politician cum social scientist, he fails to refer to any studies to prove his most fundamental point--perhaps underscoring the ambiguous nature of such data.

In the tired behavioral-reductionist tradition, he likens murder to a disease we have to "cure" even though available methods "one day will almost certainly seem barbaric." Apparently what is barbaric tomorrow is a-okay today.

The thin ice begins to crack underfoot as Koch goes on, without any explicit analysis, to invoke the names of Kant, Hobbes, Locke, Rousseau, Montesquieu, and Mill. He attempts to paraphrase this assemblage of Moral Reasoning luminaries: "natural law properly authorizes the sovereign to take life in order to vindicate justice." Koch's mistranslation of social contractarian arguments looks more like totalitarianism than democracy.

Though no one can prove that the death penalty will actually reduce crime, Koch asserts that the death penalty "must be available to punish crimes of cold-blooded murder, cases in which any other form of punishment would be inadequate and, therefore, unjust." In effect, Koch excludes as "unjust" any policy which might achieve the same decrease in crime without putting offenders to death. It is a crime that a Democrat could justify a state which can sacrifice the lives of its citizens as the means to an end.

HIS REVIEW OF Crime and Human Nature, "The Mugger and His Genes," reduces the arguments of the book to a heavy-handed call for harsher criminal penalties. But by ascribing to their book an unintended ideological content, he distorts the attempts of Wilson and Herrnstein to provide an objective criminology. Their theory sees criminal actions as results of rational judgment, and, most controversially, argues that factors such as low intelligence, sex, body structure, the reaction-time of one's autonomic nervous system, and inheritable psychotic or aggressive tendencies tend to correlate with criminality.

Koch heralds their refutation of "environmental" theories of crime as the last word, the "slap in the face" to the perceived arrogance of liberal "intellectual elites."

Instead of acknowledging the fact that the only fully explicit policy recommendation made in the book is for continued research, Koch takes the book as a mandate for "a policy of progressively severe punishment to replace the social experimentation of recent years." The theory as formulated emphasizes the role of constitutional and environmental factors in determining criminality; Koch ignores the environmental aspect, seizes the "genetic" one, and demands that we "don't spare the rod" to those who "rape and break heads."

The real-world implications of this misguided intellectual dilettantism are unpleasant. It is questionable whether a politician whose rhetoric is so polarized and whose actions are so unprincipled will be able to deal realistically with the difficult yet manageable problem of crime. It is to be hoped that Koch's recently-intensified repressive attitudes will not result in equally repressive policy, as other New York Democrats uphold the state's prohibition on capital punishment.