After a good many years in Washington I increasingly ask myself what makes it tick. Who's in charge? When it comes to writing the budget does the president do it or does Congress? When Mr. Reagan proposes more aid for El Salvador, or a tougher line on Russia, can he be sure that Congress will be behind him? Hardly. Things are on a piece-by-piece basis. You can never be sure of the result.
It is getting more confused, I think, than it was. In the old days the president and Congress usually were of the same party. But recently, while the voters chose a Republican president in four of the last seven elections (1956 through 1980), they returned a Democratic House on all of these elections and a Democratic Senate in all except the last. We have a Democratic House of Representatives, of course, right now. It's confusing. Which way do voters want the country to go? It's not easy to say (judging by party) when more than half the time control of the government has been divided.
''At such times,'' says political scientist James L. Sundquist in his valuable ''Decline and Resurgence of Congress,'' ''the normal tendency of the American system toward deadlock becomes irresistible. The president and the Congress always pledge themselves to seek harmonious collaboration but ultimately they are compelled to quarrel.''
You see a little of that in Washington now. The bickering goes on - the uncertainty, for example, over whether the administration can lead the country in negotiating with Moscow on arms, and whether Congress will back it if it tries. (Remember that the League of Nations treaty was defeated in 1920 and the SALT II treaty was submerged half a century later).
Are things becoming more disorganized? In the old days a presidential candidate had to go through the stiff screening process of the party establishment; now he spends two years in the 35 or so primaries and caucuses and like the latest two presidents has come to the White House after ''running against Washington.'' It is hard to find discipline in the system. The voters seem uncertain, too. For five successive presidential elections the percentage of voters has fallen, and in 1980, the lowest of all, only about 54 percent went to the polls. What's the use? they seemed to be saying. (In the recent West German election 90 percent voted.)
The Founding Fathers, of course, wanted to pit the president againt Congress, and the Senate against the House, for safety's sake. That would avoid a king, they thought. The system has worked pretty well, particularly in the first 150 years. But more recently there is the disturbing matter of Watergate and the increasing tempo and complexity of modern affairs. Douglas Dillon, former Treasury secretary, expresses doubts that in a world of military confrontation and economic threats ''we can long continue to afford the luxury of the division of power and responsibility between our executive and legislative branches of government.''
One lubricant that helped the system work was the political party. Parties appeared shortly after the Founders completed the Constitution. They often gave coherence and unity to politics. But the parties themselves are in decay. They don't count for as much as they did; they go through the quadrennial performance at nomination conventions but primaries are reducing their power or they are being replaced by PACs (political action committees of special-interest groups).
This could be just a phase, but I am inclined to agree with Mr. Sundquist: that it goes deeper and is ''of grave concern.'' He thinks the unique American governmental system is always threatened by stalemate and deadlock. Now perhaps we must wait for the ''surfacing of some great issue that will arouse the country to seek solutions through the political and governmental system.'' Well, maybe. It is a little alarming, however, for him to say that we may have to wait ''on something happening outside the parties themselves - some kind of sustained crisis that will arouse the people, polarize them, and impel them to organize politically, through parties, to attain their ends.'' I should prefer revival without the crisis.