The education of Ronald Reagan in the ways of the world continues into the new year. The first half of January has taught him three uncomfortable lessons.
1. Short of an outright Soviet invasion of Poland, he cannot commit the NATO alliance to sanctions against the Soviets. He could persuade the allies to recognize a Soviet role in the Polish affair so far, but in return for his own willingness to continue talking to the Soviets about weapons limitations.
2. He had to accept the unpalatable news that his ally, France, is going to ship ''nonoffensive'' weapons to the Sandinista revolutionary government of Nicaragua and train Nicaraguan pilots and naval officers.
3. He had to disappoint old California friends, including the Northrop Corporation (which builds military aircraft), by deciding to not let Northrop sell 5-FG supersonic fighter planes to Taiwan.
The dust was beginning to settle in the Polish affair by the end of its first month. On Dec. 13, Polish Army tanks had rolled into the shipyard at Gdansk (where it had all begun a year and a half earlier).
On Jan. 12, American and Soviet delegates returned to the negotiating tables in Geneva to continue talking about reducing middle-range nuclear weapons in the European area.
Which is more important: All the front page news about allied condemnation of the Soviets? Or the quiet return (Page 8, below the fold, in the New York Times) to the talks in Geneva?
There is a hope in allied quarters that the agreement they had reached at Brussels on Jan. 11 to ''deplore'' Moscow's role in the Polish affair would speed a return to normality in Poland and cause Moscow to be more cautious about continued or future interference in Poland.
The allies are committed by the Brussels communique ''to identify appropriate national possibilities for action'' if the situation in Poland continues to be unsatisfactory and if the Soviets commit further violations of international law and custom.
But any change for joint sanctions by the alliance had foundered over the original US proposal. Washington had wanted to punish Moscow by cutting off high technology machinery (which for the most part goes to the Soviets from Western Europe) but would continue to ship grain, which the Europeans do not have in surplus. On Jan. 12 West German Chancellor Helmut Schmidt commented acidly:
''US sanctions would have greater meaning if they included a grain embargo. I must admit I have heard nothing of that.''
The moral of the story would seem to be that the alliance would think about real sanctions if the American farmer would be expected to suffer as much as the West European manufacturer. Since Washington declined to ask a sacrifice of the American farmer, alliance unity was preserved only at the minimum sanction level.
Still, the alliance did hold together on the lower level. And that was a disappointment to Moscow, if one judges by the noisy Moscow protest over the mere fact that it had been judged a violator of treaties and its action deplored.
President Reagan back in Washington must have gulped when the unexpected news came in that the French government had decided to supply arms and training to the Nicaraguan revolutionary leaders. The leaders of the regime in Nicargua call themselves Marxist. They accept aid and training for their soldiers form Fidel Castro's Cuba. Washington accuses them of transhipping guns from Cuba to the rebels in El Salvador. By Reagan standards, the Nicaraguan leaders are reprehensibles who ought to be curbed or abolished, not aided by an ally.
Granted, the French are only offering to train 10 air pilots and 10 naval officers for the Nicaraguans and send a few guns and three light helicopters. The total value of the ''package'' is only about $16 million. When talking about guns that is small stuff. But it amounts to a deliberate and studied rebuke to Washington from Paris.
US Secretary of Defense Caspar Weinberger said what could be said from Washington. He said he was ''extremely disappointed'' and commented that the Nicaraguan regime ''has been heavily supported by Cuba and the Soviets and has taken positions in the area that we find very adverse to our interests.''
What else could be done? The allies in Europe do not any more take their guidance in such matters from Washington.
Then there is the matter of weapons for Taiwan.
Leading Senate conservative Jesse Helms of North Carolina thought he had the assurance of the President that Taiwan would get a fresh supply of the best of modern US weaponry. And Northrop Corporation must have expected permission to sell its new F-5G ''Tigershark'' to Taiwan. It had been designed partly with that market in view. And Northrop has been regarded as a longtime friend and supporter of Mr. Reagan's political career.
But the Polish affair has made China's goodwill seem more important than ever in Washington. And China experts cautioned that the sale of this new supersonic aircraft to Taiwan when the Chinese Air Force itself still uses mostly outdated subsonic planes could do serious political damage to the position in Peking of Deng Ziaoping. Mr. Deng is believed to have powerful enemies who dislike his modernization policies, including friendly relations with the US.
Besides, the Pentagon has been arguing that Taiwan is under no threat from the militarily weak mainland and has no real need for the more sophisticated ''Tigersharks.'' So Mr. Reagan's old political friends had to be disappointed. They were, and said so.