The United States has a major stake in quietly prodding the Philippine regime of President Ferdinand E. Marcos to move his nation toward a more democratic society and ensure an orderly succession when Mr. Marcos finally leaves office.
The US maintains vital military and commercial links with its former colony. More important, the US has been firmly committed to a democratic course for that nation throughout the past half-century - underscored by American backing of Philippine independence in 1946.
The days and weeks ahead in the US-Philippine relationship are crucial. In late July, a new National Assembly will convene. That Assembly will include a large contingent of anti-Marcos opponents who won seats in the May 14 nationwide elections. Also, the inquiry into the assassination of opposition leader Benigno Aquino Jr. concludes shortly. Mrs. Marcos testifies before that commission today. And the International Monetary Fund will soon have to decide whether to help Mr. Marcos deal with a $25 billion foreign debt.
The US would seem to be on solid ground in maintaining firm pressure on the ruling government to continue the present movement toward a more broadly based democratic society. Such leverage should be undertaken at the diplomatic level. Public pressure on Mr. Marcos - at this juncture - could backfire against the US.
The need for firm pressure seems particularly important in light of remarks made earlier this week by Mr. Marcos about what he said was stepped-up terrorism in his nation. He said that he was shocked by the growth of communist insurgency. And, he added, the situation that led to the imposition of martial law back in 1972 ''may happen all over again if we don't watch out.''
Clearly, the Philippines is facing some insurgency, as it has for a long time. But would President Marcos be tempted to use the insurgency issue to impose martial law once again - despite the fact that the Philippines have now moved closer and closer to a restoration of democratic rights, such as the recent elections?
Reimposing martial law would surely lead to widespread protests throughout the nation. So what seems more likely to be behind Mr. Marcos's latest remarks is an attempt to justify his authority to rule by emergency decree. Yet, that authority, embodied in Amendment VI of the Constitution, is expected to come under fire from the opposition when the Assembly meets next month.
What should the US be telling Mr. Marcos?
* The recent change in US ambassadors to the Philippines does not signal any change in US concern about that nation. The US still favors having an effective opposition in the Assembly as a prerequisite for a normal and orderly succession.
* The long-term security of the Philippines depends in large part on its economic well-being.
That means the government should end the widespread cronyism that in part has hobbled genuine economic development.
* The Aquino inquiry should be followed through thoroughly and fairly - to uncover all those responsible.
* The human rights situation should be improved. That would seem to mean a backing off of use of secret marshals to crack down on street criminals.
Using secret marshals cannot help having an authoritarian ring to it.
* Mr. Marcos should quickly fulfill promises to reinstitute a vice-presidency. The office of vice-president, however, should be free from direct personal domination by Mr. Marcos.