All of Washington, it seems, is involved in the long, intense tug of war over national defense and arms control policy. Depending on the specific issue, divisions in the struggle run through all camps - between President Reagan and Congress, within the White House itself, between moderate and conservative Republicans, and between the two political parties. Polls indicate these divisions may mirror a lack of consensus in the public at large over defense and arms control.
Here in the capital, the tug of war is most clearly seen in a power struggle between the White House and Congress.
''The President is taking the fight out to the opposition,'' observes Charles F. Doran, a political analyst at the Johns Hopkins School for Advanced International Studies in Washington. ''What is going on is not necessarily a showdown, but a severe test for the President's whole orientation toward national security.''
This week and next, a half dozen issues will provide the handholds in the national-security struggle.
The President shortly will take another position on the MX missile, following up on the report of his special bipartisan panel on that subject. The White House won a key contest with Senate confirmation (by a vote of 57 to 42) of Kenneth Adelman as director of the Arms Control and Disarmament Agency. The drive in the House of Representatives to pass a nuclear freeze resolution will get its third round of debate and voting April 20, with pro-freeze forces gaining strength. And Congress continues to probe White House actions and policies on El Salvador and Nicaragua.
On the spending side, the administration hopes to persuade the Senate to split the difference between the 5 percent arms buildup approved by the Senate Budget Committee and the 9.8 percent the administration has offered.
Even the deficit has become a bone of contention in the national-security debate. Many GOP leaders argue that the defense buildup must be curbed to protect economic recovery. And equally Republican, conservative economists like Herbert Stein, an economic adviser to Mr. Reagan and Presidents Ford and Nixon, counter that America is rich enough to afford Reagan's buildup.
Meanwhile, the public's will is regularly invoked as favoring one side or the other. At best, it is ambiguous. According to Roper Organization surveys, by 2 to 1 the public says Reagan's defense budget can safely be cut. At the same time the public remains fairly evenly divided in its approval of Reagan's handling of military and defense matters.
On the nuclear freeze, Roper finds that the public reflects the diversity of views seen in the House legislative battle, where 29 amendments frustrate fast action. Only 9 percent of the public oppose a freeze outright. Thirty-six percent favor a freeze if the Soviet Union cuts back its strategic forces to a level equal to the US, 20 percent support a freeze on missile production now even if the Russians have more missiles, 14 percent favor a freeze if the US catches up, and 10 percent would support a freeze when the US gained superiority.
The White House and freeze opponents are exploiting this lack of consensus to put off what appears like an inevitable Reagan defeat. At a breakfast meeting with reporters, White House counselor Edwin Meese III said the failure to conclude House action on the freeze Wednesday, the second postponement in a month, shows the freeze proponents are confused. He also argued that the freeze is more a political test of the Democrats' new membership in the House, as well as being what he terms ''irrelevant'' and ''counterproductive'' on its face.
In Congress, the balance of power on the freeze issue has definitely shifted against the President. Last August, a freeze resolution narrowly lost by two votes. In key tests this week, the pro-freeze forces showed a decisive 25- to 30 -vote edge.
The Democratic leadership predicts a final margin of 60 to 100 votes for the freeze resolution in its final form. Democrats did not press for a final vote this week because at least six more hours would have been needed for debate and voting. This would have pushed deliberations into the early morning hours Thursday, when 24 members were scheduled to fly to California for colleague Phil Burton's funeral.
Republican House support for the freeze has also grown since the 1982 election. ''We could have finished if we went late tonight,'' said Rep. Jim Leach (R) of Iowa, a freeze proponent. ''What is at stake is not the precision of language as much as the generality of the message: For this President and all future presidents, arms control is not a political liability.''
The division among Republicans in the House and Senate runs at times between moderates and conservatives, and at times between conservatives themselves. Some lines appear deeply fixed - like the majority favoring cuts in Reagan's defense buildup. Other lines, such as on the Adelman issue, tend to zigzag through the ideological and party line-ups.
''The settling in has been heaviest on the defense budget,'' says Robert J. Pranger, director of international programs at the American Enterprise Institute and a former Nixon defense official.
The defection of GOP senators like Indiana's Richard Lugar, who backs reductions in Reagan's 1984 defense budget, is seen as a crucial sign in the arms debate. Senator Lugar heads the Republican Senate election drive for 1984, when the Democrats threaten to regain Senate control.
''All the percentages have gotten symbolic to some extent,'' Lugar says. ''A majority of people think we're spending the right amount. That was not the case two years ago. The 5 percent real growth (in defense outlays) President Carter was pushed to . . . has become a place where most people - Democrats and Republicans - have come to feel comfortable.''
''It'll be 5 or 6 percent,'' he predicts for the final defense budget hike.