The Reagan presidency has not begun officially, but in fact the next President is already playing a practical role in world affairs. His most important move of the past week was to cross into Mexico for a courtesy call on President Jose Lopez Portillo of Mexico. One aim of the visit, obviously, was to encourage a climate in which the Mexicans might someday allow Mr. Reagan's countrymen to buy more of their oil.
While Mr. Reagan was seeking to build toward that better climate in Mexican- United States relations, Henry Kissinger was roaming the Middle East. He claimed he was only a tourist revisiting old friends. But there was little doubt in anyone's mind that he was on a reconnaissance mission for the incoming US President among those "old friends."
There need be no mystery about the purpose of that mission. The signs are clear enough that the new Reagan team knows that access to enough oil to keep US industry working is a priority need. The Middle East and Mexico are prime areas when one thinks about oil.
There was a third move of the week that also exposed the practical side of the emerging Reagan attitude toward the outside world.
Anna Chennault, once known as the "tiger lady" of the oid China lobby, turned up in, of all places, Peking. She was travelling with the new deputy leader of the Republican majority in the Senate, Sen. Ted Stevens of Alaska. They had a two-hour session with Deng Xiaoping, the most important person in the Chinese government. At the end of the meeting Mrs. Chennault observed that people must be "courageous enough sometimes to change their positions" and Senator Stevens implied that the Reagan administration might sometime be willing to talk about guns for China.
Mrs. Chennault left Peking headed for Taiwan. In a recently published biography she called recognition of China "wrong- headed" and a "betrayal" of Taiwan. She is a former Republican national committeewoman and a longtime backer of Mr. Reagan. Mrs. Chennault has changed her own position on China dramatically by going to Peking and talking to Mr. Deng. The joint Chennault-Stevens visit at this time is assurance of the Chinese in Peking that the Reagan administration has no intention of undoing the new China policy launched by President Nixon and carried along by Presidents Ford and Carter.
And Mrs. Chennault's travels have a further dimension. By first visiting Mr. Deng in Peking, then going to see her own old friends in Taiwan, she is in fact a new channel of communication between the two Chinas. There has been a tentative dialogue going on between the old and new in China. Mr. Deng has repeatedly asserted that his government in Peking has no intention of using force against the Nationalist Chinese on Taiwan. His line is that they are entirely free to go their own economic and political way. But he would like to have official relations that would give some substance to the doctrine they both embrace -- that there is only one China.
In theory an incoming president does not touch foreign policy until he is actually sitting in the Oval Office at the White House and in full authority. Circumstances of the moment have made that impossible.
From election day in November Mr. Reagan was a factor in the negotiations with Iran over the hostages. It is there that he has made his most important foreign policy move. When the negotiations reached a critical point just before Christmas, he spoke out in a manner designed to make the Iranians realize that right now is their best chance for favorable terms.
Probably no one, even in Tehran itself, can be sure that there will be a moment when the government in Tehran can in fact release the hostages. President and prime minister are themselves, in effect, prisoners of the fanatical mullahs still in dominant position in that country.
But at least Mr. Reagan was able on Dec. 24 to make the point that Iran has nothing to gain by waiting until after Mr. Carter leaves the White House. US terms will be no softer; by implication, harder.
Along the way Mr. Reagan was prompt to put an end to conflicting noises coming out of the foreign-policy transition team. On that team were a number of persons with strong personal points of view on various subjects, such as the proper handling of troubled Central American countries, the Middle East, and China. Mr. Reagan put General Haig in charge as prospective secretary of state. General Haig moved out the transition team. From that moment there has been a welcome absence of personal, private policymaking.
Partly that resulted from the visit to Moscow by Sen. Charles Percy of Illinois, incoming chairman of the Senate's Committee on Foreign Relations. Pro-Israel members of the transition team leaked excerpts from supposedly confidential reports from the US Embassy in Moscow about things the Senator said on the subject of the Middle East. This immediately raised a question about future Reagan policy toward Arabs and Israelis. It also embarrassed Senator Percy, whose support is critical to future Reagan foreign policy. There have been no more leaks since General Haig took over.
In other words, President-elect Reagan has already done several useful and practical things about foreign policy. He has stilled the welter of conflicting voices about future policy. He has opened what might well become a productive dialogue with Mexico. He has put some heat under the Iranians which just might make them more eager to settle the hostage issue before inauguration day, if possible. And he has put to rest any doubt about China policy. He is not going to abandon the reopened relations with China that President Nixon launched.
All of which seems reasonable, practical, and headed in constructive directions.