Reagan in the Pacific

President Reagan has his work cut out for him on his Asian trip, now just five weeks away. Trouble in the Philippines is only part of it. In Guam, Indonesia, Thailand, South Korea, and Japan, Mr. Reagan has to get his messages right.

The overall theme, of course, will be to reaffirm the free world alliance in that populous region. As a foreign defense policy venture, the tour's purpose will be to shore up US security ties from the Sea of Japan to the South China Sea.

But first the Philippines. The recent assassination of moderate opposition leader Benigno S. Aquino Jr. has been followed by crowd violence. The threat to the President's personal safety is obvious. The judgment of those charged with protecting the President will be one factor in a decision whether to stop in Manila. So will Mrs. Reagan's views. Presidents don't like to be seen cancelling events for reasons of physical safety, so a no-go decision will likely be attributed to someone other than Mr. Reagan.

Either way, whether he goes or not, the Philippines hand is hard for Mr. Reagan to play.

If he goes, he's going to be implicated to some degree on President Ferdinand Marcos's side, in the eyes of fhilipinos and much of the world, for the nature of the regime and in the followup to Aquino's felling. The objectivity of the commission, appointed by Marcos to study Aquino's death, is suspect. Obviously the administration sees the Manila visit largely from a security standpoint. Without the two Philippine bases, the US 7th fleet would be adrift in that part of the Pacific. The fleet's home base is Japan.

But such a visit is also a political event. What message does the Reagan administration want to give? If the White House cancels the visit absent clear evidence the Marcos regime was not responsible for the assassination - not likely given the nature of the inquiry - it would give radical as well as moderate opponents of Marcos a signal that the US is taking hands off the situation and leaving Marcos to fend for himself. To embrace Marcos too closely would be as much a mistake. A case can be made that Reagan should work out an understanding with moderate leaders about how an eventual transition from Marcos's rule would take place. Jimmy Carter failed to make such an arrang-ement before his visit to Iran in l978. Transition in the Philippines could be imminent. Marcos has largely squandered his earlier support. Marcos could hermetically seal off the area Reagan would visit, reimpose martial law. But to many expert observers, Marcos's grip on power is loosening. At least this appears to be the reason Aquino risked a return to his homeland. Reagan faces a classic policy choice with his visit to Manila. The time to send his people ahead to make the necessary political preparations is now.

Elsewhere on his Pacific tour, Mr. Reagan is expected to bear a hawkish message. In Guam, he could emphasize the enormous air base there, possibly as a lever over Marcos's threats to link Philippine bases to a Reagan visit. Guam will also be touted as something of an American success story, while the islands in the region debate trust territory status.

Thailand will also get a defense theme, with mention of Soviet clients in Kampuchea. Reagan is expected to hammer away at the evils of Soviet designs in Indochina. Afghanistan will be underscored.

In South Korea, the downing of KAL flight 7 will obviously be deplored, taking some of the attention away from a Reagan recommitment to another controversial regime.

In Japan, Mr. Reagan will want to avoid negative statements about Japan's defense program. Mr. Nakasone faces his own domestic discipline on defense. He had to cut back defense outlays to less than l percent of Japan's gross national product - about to the level under his predecessors. To be fair to Nakasone, defense spending is the only part of Japan's budget that's been allowed to grow. Nakasone was forced to trim his defense plans below what they were a year ago, in negotiations with the finance ministry.

Another chapter in Mr. Reagan's Asian travels might come next year, with a trip to the People's Republic of China. China, despite the victory inside the Reagan administration of those who want to liberalize trade, does not yet fit into the Reagan free-world family. China's a separate chapter. The concern there is that Defense Secretary Weinberger, in his sortie there next week, will find the Chinese attaching too many strings, at Taiwan's expense, to trade expansion, especially military trade.

So there's enough work for Mr. Reagan to do in the Asian Pacific to merit a trip there. But he will find it no easier than his other trans-oceanic tour, to Europe last year, to set the right tone and take the right tack.