When the government of Nicaragua let La Prensa resume publication six months ago as the only anti-Sandinista newspaper in the country, the move was widely hailed as an important gesture of good faith.

But now that gesture has turned sour. La Prensa has been forced to cease publication indefinitely because its supply of newsprint, controlled by the government, has run out.Though the Sandinistas claim an expected shipment of newsprint failed to arrive and they aren't to blame for the closure of La Prensa, that alibi won't wash.

Otherwise, why is it that the two other newspapers in Nicaragua, both pro-government, have enough newsprint to keep publishing? How can the government justify its failure to make good on its commitment to make available the hard currency needed to buy newsprint? And how can the government explain away its constant harassment of La Prensa?

The government not only keeps using Sandinista television to accuse publisher Violeta B. de Chamorro of treason, but also apparently assigns an officer to remind her by telephone each day that newspaper editors are mortal. A harmless ploy? Not when one considers that the same tactics were used against Senora Chamorro's husband until the day before he was killed.

When La Prensa was allowed to re-open last October after a 15-month shutdown, the move was part of a regional peace plan agreed to by the Sandinistas. This week's closure of the newspaper shows just how far the Sandinistas can be trusted and just how closely any permanent peace pact resulting from current negotiations ought to be monitored for violations.