US President Ronald Reagan's long opposition to the Panama Canal treaties of 1977 has not prevented him from supporting their successful operation now. This welcome development was symbolized by last week's meeting in Washington with Panama's President Ricardo de la Espriella. Mr. Reagan said he looked forward to a ''warm working relationship'' between the United States and Panama, sentiments echoed by the visiting leader.
The fact is that the joint operation of the Panama Canal, as agreed in the treaties, has been working well for three years. Final figures for fiscal year 1982 are expected to set new records in revenue, tonnage, and number of ships. Part of the reason is oil traffic from Alaska's North Slope, which has risen by more than 25 percent over 1981.
Panama Canal Commission officials note with pardonable pride that the pace has been maintained - from 13,884 vessels in 1981 to about 14,300 in 1982 - despite continual increases in the size of ships. New tugs and towing locomotives have helped to reduce the average time a ship stays in canal waters before and during transit from 41 hours in 1981 to 35 hours since April of this year.
There has been some friction over labor relations, including pay differentials and retirement arrangements. But these are bureaucratic matters that can be solved, as President de la Espriella has said.
Meanwhile, the progress of the canal offers a dramatic alternative to the unrest that many feel would now exist if the two countries had not reached a treaty arrangement for orderly transition to Panamanian participation and authority. Mr. de la Espriella once went so far as to say that Panamanians would have mounted a defiant protest resulting in US invasion and armed occupation of his country.
Instead, the Panamanian and US presidents honor each other. And all Americans - North, South, and Central - might pause to honor the two nations' previous leaders who struggled so hard over so many years to bring the treaties to pass.