THE PRINCIPLES of progressivism should never be abandoned. Those principles are not served, however, by voting for a third-party candidate who stands no chance of winning the presidency. Such misdirected idealism can only help put Ronald Reagan into the White House. Difficult as it may be for some liberals to swallow the idea of four more years of Jimmy Carter, he is infinitely preferable to Reagan and should be re-elected.

Ronald Reagan's nomination by the Republican Party scared us; that he may become the next president terrifies us. A Reagan-appointed Supreme Court would irreparably damage civil liberties guaranteed in the Constitution. destroy the delicate balance of world peace and turn back the clock for social and economic justice. We are not willing to risk the gains of the last 50 years--and the values of peace, equality and justice--for a fleeting, fanciful wisp of a party and candidate that might never again be heard from after November 4.

To suggest that a Reagan presidency would be equivalent to four more years of Carter is ludicrous. Where Carter has appointed more women, Blacks and Hispanics to the federal judiciary than all previous presidents combined, Reagan's record shows a complete lack of concern for such groups. Where Carter successfully pushed for extension of the ratification deadline for the Equal Rights Amendment, Reagan opposes the ERA. Where Carter undoubtedly would appoint justices who will safeguard civil liberties, Reagan and the platform he runs on state that nominees for the Supreme Court would be screened for their opposition to abortion; we pale at the thought of five clever, conniving William Rehnquists making decisions that would affect us for decades to come.

Where Carter has secured a windfall profits tax to finance development of alternative energy sources, Reagan blindly insists that we will simply "produce" more oil and that the free enterprise system, unencumbered by environmental guidelines that Carter has supported, will fill in the gaps. Where Carter has nominated sane, balanced people to guide the country's future in nuclear energy, Reagan would pull out all the stops. Where Carter has taken steps to curb industrial pollution, Reagan thinks pollution comes only from volcanoes and trees.

We cannot defend Carter's record on the economy, but Reagan would be worse. To argue that one can slash taxes (Reagan supports the Kemp-Roth proposal), increase defense spending and balance the budget strikes us, as Reagan's own running mate (and a terrifying personality in his own right) has said, as "voodoo economics." Where Carter has consistently supported labor, Reagan still questions the validity even of the minimum wage. Reagan would not stop with trimming domestic programs; he has promised to eliminate some agencies (the Departments of Energy' and Education, for example) that Carter has established.

Where Carter led the fight to return the Panama Canal, Reagan might have sent in the marines to "keep the canal." Where Carter delicately negotiated normalization of relations with the People's Republic of China, Reagan's ill-considered statements about Taiwan have already jeopardized our new friendship. Where Carter did what nobody thought could be done and engineered the Camp David peace treaty, Reagan gives no indication of how his dreams for the Middle East could be achieved. Where Carter has raised the issue of human rights, albeit inconsistently, Reagan would cast off the notion entirely because of the need, as he puts it, "to accept the world as it is."

Where Carter negotiated an arms control treaty that he still intends to lobby through Congress, Reagan would scrap SALT II and challenge the Soviet Union to an arms race. Where Carter has exercised restraint in dealing with the Soviet combat troops in Cuba and invasion of Afghanistan, Reagan threatened to blockade Cuba and to teach the Soviets a lesson after Afghanistan. Where Carter, caught in the throes of the new militarism, reinstituted draft registration, Reagan's record suggests he might use the new recruits to fight for some new "noble cause." Where Carter has learned from four years of mixed success in foreign affairs, Reagan might misplace his three-by-five cards and stumble into the O.K. Corral with guns blazing.

IN SUM, while we are less than pleased with Carter's record of four years, he is vastly preferable to a man whose understanding of diplomacy in the nuclear age rivals his mastery of Darwinian theory.

While some people argue that Rep. John B. Anderson (R-Ill.) is an attractive alternative to the major party candidates, he cannot win. Nor is he the liberal he says he is. A hawk during the Vietnam War (he condoned the invasion of Cambodia and suggested President Nixon should receive the Nobel Peace Prize), he has consistently voted against labor, for nuclear power, and for increases in military spending. He opposes even the modest national health care plan supported by Carter. As an independent, he would find it impossible to work with the major parties in Congress.

Like Anderson, Barry Commoner cannot win. We are not willing, moreover, to cast our lot with a man who has never demonstrated that he can lead, or with a party that probably will crumble after November. Much of what Commoner says strikes us as reasonable, even desirable. His energy program emphasizing conservation and solar power, his support for economic justice and his promise to cut defense spending are sound ideas. But a citizen's vote represents his prime opportunity to turn his ideals into reality. Barry Commoner is not part of reality. Those who seek to advance the principles of peace and progressivism would do best to cast votes where they will count and continue their pursuit of peace, equality and justice in other forums.

Liberals who today are tempted not to vote or to cast a protest vote in hopes of building a challenge to the New Right must remember the lesson of 1968. In that year, many college students disdained to vote for either Hubert H. Humphrey or Richard M. Nixon because they considered both candidates to be neanderthals. Perhaps as a result, Nixon was elected by a margin of 1 per cent of the popular vote. The nation paid a heavy price for the liberals' refusal to vote for whom they considered the lesser of two evils. The same must not happen in 1980.