THE REAGAN administration does not want you to travel to Cuba. Isolation of the Caribbean communist state is the objective, and prohibiting the spending of hard currency there is one way to keep the pressure on. But it's not an easy thing to limit travel by American citizens. The Supreme Court has held that freedom to travel is a constitutional right closely related to rights that the Bill of Rights protects. A 1978 amendment to the Passport Act prohibits the executive branch from limiting peacetime travel without the authorization of Congress except for health and safety reasons.

What did the Reagan Treasury Department do in the face of these restrictions? Last year, it issued regulations prohibiting most travelers from using dollars to pay for expenses incident to travel to Cuba. But there was a roadblock to this approach: a 1977 law requires the president to declare a national emergency and to consult with Congress before imposing such financial restrictions. So, instead, the Treasury relied on the Trading With the Enemy Act, a 1917 statute giving the president broad powers to impose economic sanctions against foreign countries. This week, the U.S. Court of Appeals in Boston struck down the Treasury regulations and held that the government had to comply with the 1977 law.

This case is troublesome in two respects. The court was concerned only with the procedural aspect of the regulations and with the fact that the requirements of the 1977 law had not been observed. Our misgivings go to substance. After 14 years of severely restricted American travel to Cuba, the Carter administration lifted all travel-related foreign exchange and passport barriers in March 1977. Other commercial and economic sanctions remained in force, but six years ago it was wisely decided that travel expenditures have only a small monetary impact, and these are far outweighed by the advantages to be gained when citizens are allowed to journey abroad. The Carter administration's easing of these barriers was hailed as a step toward normalizing relations with Cuba. The Reagan regulations were a clear signal that the process was to be reversed.

A free society, strong and certain in its own values, is not afraid to allow its citizens to see how others live, to talk with those with whom there are strong disagreements or to open its own doors to nonviolent travelers with unpopular views. Tourist dollars won't turn the Cuban economy around. Travel restrictions hurt Americans more than they harm Havana. The Treasury should accept the court decision and lift the barriers once and for all.