''I'm not saying that's a good way to make defense policy, but that's the nature of the beast.'' Over scrambled eggs and sausage, Texas Republican John Tower, chairman of the Senate Armed Services Committee, was describing to reporters this week one of the major faults with the way the United States manages its multibillion-dollar defense establishment: Members of Congress buy weapons that may have questionable military value, but they bring jobs to the voters back home.
As the White House pushes on with America's largest peacetime military buildup, these and other problems with the way the defense establishment works - and the need for solutions - are becoming increasingly evident.
Some of the recent indicators: The Pentagon rushed to spend its vast sums before the close of the just-ended fiscal 1983; the Defense Department is rife with battles and service rivalries over limited resources and how to allocate them; Congress is demanding more control over weapons testing and warranties; and there are attempts to inject more competition into military procurement.
Many of the calls for change are coming from Republicans and conservatives. Senator Tower is holding hearings on defense reform and next week will begin to probe the high cost of some military spare parts. And since he generally favors bigger defense budgets, when the influential John Tower speaks on the subject, people listen. The diminutive Capitol Hill veteran is retiring from the Senate next year, and has been prominently mentioned as a possible defense secretary in a second Reagan term if Caspar W. Weinberger tires of the job.
While much criticism of the system centers on the Pentagon, Tower says, ''A lot of the problems we have are as much Congress's fault as anyone's.'' And, he says, without changes things could get worse.
He notes that the ''bow wave'' of the defense buildup is cresting just ahead. Many new weapons, especially the 600-ship Navy, already have been approved and now must be paid for. Unless the recovery is reversed and federal deficits become a bigger political problem, there will be little incentive for Congress to cut back on the new planes, tanks, and ships already approved.
In a recent Monitor interview, Mr. Weinberger said that he will push to restore in the 1985 defense budget the items recently cut from the 1984 fiscal year, just begun.
''Obviously substantial increases are needed because the whole plan of the President was to acquire needed modernization as well as improving readiness over a five- or six-year period,'' he said.
This means a defense budget that will likely top $300 billion next year. At the same time, the administration is trying to show that it can be a tough manager of the Pentagon. Defense officials announced Tuesday that they had won $ 3 million in criminal fines and civil penalties from a spare-parts producer who pleaded guilty to filing false claims against the federal government.
But that may not be enough for congressional critics, including many Republicans. Last week, the GOP chairmen of two Senate committees challenged what they termed the Pentagon's recent ''spending spree.'' They asked the Defense Department's inspector general to investigate reports that some $4 billion in contracts were awarded the last day of fiscal year 1983 to avoid having to return money to the US Treasury.
Sen. William S. Cohen (R) of Maine is pushing a bill to require more competition in awarding US contracts. This would particularly affect the Pentagon, which accounts for 80 percent of all contracts worth more than $10,000 .
Sen. Mark Andrews (R) of North Dakota wants to require weapons makers to include a warranty that their products will work. Republicans have led the fight to establish an independent office to test new weapons.
Tower doesn't like what he regards as such congressional ''micromanagement'' of defense matters. But he does say changes are needed. The US is one of the few countries that budgets for defense a year at a time. Because most defense planning and procurement must occur over several years, many observers - including Tower - suggest that a more stable, more rational, and perhaps less politicized defense system should include a two-year budget cycle.