Is it the third-year bailout? Are the ''pragmatists'' jumping ship? Would a second Reagan term be more conservative?
These are the kinds of questions that titillate political observers, as White House staff members depart the scene and rumors fly about longings of others for fresh pastures. The most recent stir was caused by a report that White House chief of staff James A. Baker III had expressed interest in a job as the major leagues' baseball commissioner.
This bit of intriguing news came on the heels of an announcement that David R. Gergen, White House director of communications, had resigned to take up a post at Harvard. Kenneth M. Duberstein, who has played such an effective role in the White House liaison with Congress, is leaving to join a lobbying firm.
Washington likes nothing more than ruminating on personality conflicts within the White House and the significance of tensions in this or that policy area. The Reagan administration has its share of interbureaucratic squabbling and frictions between the conservative hard-liners and the so-called pragmatists. But political scientists seem agreed that the Reagan White House runs more smoothly than most - although not as smoothly as the Reaganites like to portray.
In this instance, the personnel shifts are attributed largely to the third-year and fourth-year exodus that often occurs in an administration when overworked, battle-fatigued aides begin thinking about their future and seek to take advantage of their White House ties before an election.
''Three years is a long time to work 18 hours a day, seven days a week,'' one Reagan political operative comments. ''You can't live like this forever, and if you want to build a future, you have to capitalize on your job. Everyone wants to come out better than he went in.''
''It's a mistake to attach any ideological significance to this,'' says Charles F. Doran, a political scientist at Johns Hopkins University. ''We are seeing individuals who in some cases have not given their whole career to politics and who, having fought many battles, are tired and not interested in facing a second administration and taking the risks associated with an election.''
It is also speculated that it does not hurt White House aides to have reports circulating about other employment opportunities. Mr. Baker, for instance, is said to be interested in a Cabinet post rather than continuing as chief of staff , a grueling job that makes him the inevitable target in intrabureaucratic conflicts. Recently, at the time of the controversy over Interior Secretary James G. Watt, Baker sought the post of national-security adviser, a move that would also have elevated Michael K. Deaver and Mr. Gergen, but Baker lost out to Robert C. McFarlane.
''With that shift not happening, Baker will be active running the political campaign,'' says a knowledgeable observer. ''That's not insignificant. He will have greater control in the party organization, he'll get away from the internal bickering and the grind, and recharge his batteries. In a second administration he's an obvious candidate for the Cabinet.''
As the election draws nearer - and President Reagan is scheduled to announce his candidacy officially on Jan. 29 from the Oval Office - attention naturally focuses on political strategy. Dr. Doran suggests that the political professionals will now take over in the White House while the technicians and those who are more oriented toward issues of policymaking will have less influence.
This is why economic adviser Martin Feldstein ran into trouble with the President: He was seen as hurting the President politically. ''There is room for divergent opinions in the administration, and the Reagan style is to encourage this,'' says a Reagan campaign official. ''But there is no room for public disagreement once a decision is reached, especially in an election year. So people had to make sure Feldstein understood this.''
Dissent in the White House is viewed as having its beneficial side, however. Stephen Wayne, a presidential scholar at George Washington University, suggests that infighting is good, because it annoys the President and ''forces him to be President'' - that is, to step in and resolve the dispute.
Dr. Wayne sees the restlessness among the pragmatists as preliminary to postelection appointments which could turn out to be more conservative. In his opinion, the ideological idealism of the first term has been tempered by the pragmatists because of the power of Congress, the need to be reelected, and pressures from other governments of the world.
''But if Reagan is reelected,'' Dr. Wayne says, ''there might be a greater tendency to 'Let Reagan be Reagan.' This says that his actions would be more in sync with his rhetoric and that he would be more distant from decisionmaking.''
''A lame-duck president tends to be himself more,'' agrees James Sundquist, a political scientist at the Brookings Institution. ''Nixon and Eisenhower both made a turn to the right in their second terms.''
Other analysts believe that, despite Mr. Reagan's frequent tough-line speeches designed for the ear of the right, he remains the pragmatic politician and would continue to show flexibility in order to get programs and policies implemented. His second term as governor of California bears this out, they say.
''Reagan's record shows he has a very practical strain,'' says a campaign official. ''He looks at problems not only from the standpoint of ideological purity. He wants to solve problems.''
''The pragmatists have not been weakened at the White House,'' says a former insider. ''Baker and Deaver remain, and McFarlane, too, is a pragmatist. Moreover, Reagan is so strong in his ideological convictions and so comfortable that he is capable of greater pragmatism.''
It is also thought that the news media have made too much of the ideological distinctions among White House aides and mislabeled some advisers as ''moderates.''
''They are all conservatives,'' says Dr. Doran. ''Baker is as conservative on most things as the pure Reaganites. 'Pragmatist' is therefore a better term than 'moderate.' The pragmatists prefer to win than take an ideologically 'moral' stand. They listen to the technical people, look at the realities, and then make a judgment.''
The view that there is little ideological divergence in the White House is borne out by a study conducted by Prof. John H. Kessel of Ohio State University and presented to the American Political Science Association this fall. After probing the Reagan staff, Professor Kessel concluded that, once personalities are taken into account, there were no differences between President Reagan's policy preferences and those of his staff. He also found, based on an elaborate system of ratings on various issues, that the Reagan staff is more conservative than the Nixon or Carter staffs.
Another conclusion was that the Reagan White House has functioned more harmoniously than previous administrations. But some analysts believe that frictions have developed in recent months and that even the departure of two key aides indicates there is discontent at the top.
''There was unusual harmony in the early years,'' Dr. Sundquist comments. ''Now factions seem to have arisen and things have reverted to what is found normal in such a high-pressure situation.''