Washington — As the Reagan administration looks ahead at its second term, the talk in Washington is of factions and alliances within the administration. How to deal with the Soviet Union on arms control and - less directly - in Central America are the focuses of apparent tugging and hauling as agendas are drawn up and priorities set.
It is unclear yet whether the President will pay closer heed to advisers in the Defense Department (often described as ''hard-liners'') or to those of more moderate persuasion at the State Department. One of the reasons Mr. Reagan canceled a breakfast meeting with reporters last week is precisely that he hasn't decided such things.
Some observers here saw significance in the fact that last week the President met with Secretary of State George Shultz and national-security adviser Robert McFarlane - but not with Defense Secretary Caspar Weinberger - to talk about foreign policy emphasis for the next four years. Speculation was further aroused when it was learned that Mr. Shultz had been asked to stay on but that no such formal request had come from the White House to Mr. Weinberger by week's end.
On the other hand, the President warmly welcomed representatives of the American Security Council Foundation and the Coalition for Peace Through Strength (of which Mr. Reagan was an early member) to a White House reception. There, the two strongly pro-defense groups presented a report in which the administration was urged ''to coordinate a long-term economic and political offensive to roll back communism.''
And there seems little doubt that Weinberger - a longtime friend of the President who served as California state budget director when Mr. Reagan was governor nearly 20 years ago - will remain in charge at the Pentagon. Similarly, there is no sign that Weinberger's top assistant for national security policy - Fred Ikle - will not remain an influential figure.
Thus, it is instructive to hear what Weinberger and Dr. Ikle been saying lately about arms control and Central America, topics which dominated radio and television broadcasts over the weekend in which these senior administration officials were questioned by reporters from several news organizations, including The Christian Science Monitor.
Both Weinberger and Ikle look beyond the recent flap over the possible shipment of Soviet-built MiG fighters to Nicaragua to the possibility of Moscow gaining influence in this hemisphere.
Pointing to what he continually calls ''the very large and increasing amounts of armaments coming into Nicaragua from the Soviet Union,'' Mr. Weinberger said on the Cable News Network: ''When you have one country outside the hemisphere pouring in weapons to a small country in this area far beyond what that country needs for its defense, you have to worry that some of the fundamental thinking behind the Monroe Doctrine, which has guided us since the formation of our country, is being violated.''
''We don't want powers from outside this hemisphere - or, for that matter, from inside the hemisphere - to impose their regimes on other countries,'' says the Swiss-born Ikle. He adds that the US, as the most powerful member of the Organization of American States (OAS), has an obligation to others in the region (as well as their support) to see that this does not happen.
''Cuba has been expelled from the organization (the OAS), and that gives an indication as to how other hemispheric countries feel about the implantation of an alien-type dictatorship in the hemisphere,'' Ikle told Voice of America panelists. ''So I would judge from that that should the Sandinista totalitarian communist regime become consolidated in Nicaragua, that would be considered very alien politically by the other members in the hemisphere.''
On arms control, both officials are very cautious about agreeing to anything that does not include (as Weinberger puts it) ''complete verifiability.'' Both stress what they see as persistent violations by the Soviet Union of existing treaties, and both cite the strategic arms limitation agreement signed by Jimmy Carter (but not ratified by the US Senate) as an example of a ''bad'' accord.
Ikle warns that it may be ''well nigh impossible'' to come to any comprehensive arms control agreement that can be adequately verified, and cautions against ''creating arms control agreements and limiting certain things (simply) because we can verify them.''
While some officials have hinted that the US is ready to offer ''new options'' should the Soviets return to the stalled arms talks in Geneva, Weinberger argues that the US has been ''extremely flexible already.'' And, he says, ''arms control shouldn't degenerate into a search for something that the Soviets will agree to.''