President Reagan, who sent one message to the Philippines a while back by cancelling a trip of his own, has just sent another by dispatching a heavyweight confidante, Paul Laxalt. The senator's evident mission is to communicate American anxiety over the way President Ferdinand Marcos is running his country into the ground and, beyond that, to measure whether Mr. Marcos, who has been 20 years in power, has the physical health and the political capacity to arrest the rot.

This is, when you think of it, a sorrowful turn. The United States, in the course of making the Philippines a colony, also made it a democracy, and thus never felt guilty afterward. On the contrary, it felt proud, and it has often been insensitive to the resentments stirred among many Filipinos by American paternalism. A pattern developed in which successive administrations largely deferred to Mr. Marcos on grounds that he ran a democracy, however imperfect, and offered the United States the immensely important strategic benefits of the Clark and Subic military bases. Only now, when the democratic aspect has failed to produce a solid political process and when indefinite access to the bases can no longer be taken for granted, is Washington being compelled to step up concern.

The question is whether the sickness is so far advanced in the Philippines -- the mal-development, the corruption, the insurgency -- that the very effort to anticipate a communist takeover risks aggravating the disease. The models of Iran and Nicaragua are much on the American mind: in those places a belated and uncertain American effort to steer a friendly authoritarian regime toward reform was overwhelmed by revolution with a bitter anti- American flavor. American conservatives, who made much of Jimmy Carter's frustrations in the two places, have been sensitive to the perils in the Philippines. Usable models of transition in these circumstances are in short supply.

Some Filipino democrats, desperate and -- some of them -- accustomed to dependency, believe that it is up to the United States to rig the various available sticks and carrots to ensure a transition to a more stable democratic order -- without Ferdinand Marcos and his family, friends and hangers-on. But the Reagan administration, while aware that the Marcos circle's grip on power hinders such a transition, hesitates to take the responsibility for easing the Filipino leadership out. The administration is attentive to the dilemma. It will have to be exceptionally skillful as well. No one -- least of all Mr. Marcos -- should be in the slightest doubt that President Reagan is determined to see democracy and the American connection endure.