REPUBLICAN presidential candidates, like the Democrats, present a range of views on trade. Most noisily at one end of the Republican spectrum is Jack Kemp. The same politician who's responsible for some of the worst economic ideas of the Reagan years, from the overlarge Kemp-Roth tax cut to his advocacy of a return to the gold standard, takes the right position on trade. Mr. Kemp stands foursquare against trade barriers -- ours or anyone else's -- and solidly for free trade. A critic of economic institutions in other respects, Mr. Kemp appreciates how the lowering of trade barriers in the post-World War II years has led to more trade and more economic growth everywhere, and he knows that trade barriers, once in place, are hard to get rid of. He champions free trade at some political risk, as a congressman from suburban Buffalo, and has offered to step forward to debate Richard Gephardt on the issue. Give him full marks on trade.

Give good marks also to some other Republicans. Pete du Pont's experience as governor of Delaware convinced him that free markets can power growth far better than government intervention; a spokesman says "he doesn't have a protectionist bone in his body." Alexander Haig, after stints at high levels of government and in the export-minded arms industry, decries "the disaster of a protectionism that could cripple world trade and wreck the international finance system" and wants to see a lowering of barriers and an end to agricultural export subsidies.

From George Bush and Robert Dole the rhetoric is milder, but both have refrained responsibly from Japan-bashing and from promising protection to local industries. Mr. Bush, ever the optimist, sees protectionism as "a defeatist attitude," though he grants that we need to make sure our trading partners play by the rules. Sen. Dole has tended to support administration positions on trade and opposes the Gephardt bill. The Reagan administration's support for free trade is strong in principle, and the president has sometimes taken political risks for it -- though he has also sometimes caved in to demands for protection from big industries (autos) and little (motorcycles). A Bush or a Dole administration, to judge from the candidates' tone, would take similar positions.

On the other side is Paul Laxalt. In the Senate he voted for the textile protection bill Mr. Reagan wisely opposed, and last month Mr. Laxalt appeared in South Carolina -- which votes the Saturday before Super Tuesday -- and was endorsed by textile magnate Roger Milliken. If Mr. Laxalt is ready to support a specific industry, Pat Robertson seems to favor the same general approach as Mr. Gephardt; he serves "due notice on the Japanese and our other trading partners: either give us free and fair access to your markets -- or we will shut down America's markets to you." But these two candidates are the exception. The Republicans may be the party of Reed Smoot and Willis Hawley, but for 1988 their candidates tend to take a more enlightened stand on trade issues than the Democrats.