Rep. Patricia Schroeder (D-Colo.) had the audacity to step behind the lectern in the well of the House of Representatives during the recent debate on the Pentagon money bill and warn her elders on the Armed Services Committee that they were making themselves obsolete.

Although it did not take those elders long to shake off her warning and vote millions more than President Carter had requested for the national defense, what Schroeder had to say is worth a closer look than the House chose to give it that day.

For what Schroeder sees is a breakdown of the legislative process as an unexpected by-product of the budget reforms Congress has made in hopes of getting a better grip on total government spending.

The heart of the reforms was the formation of the House and Senate budget committees, which recommend how much the government should be allowed to spend each fiscal year. A ceiling figure is established for various categories, including national defense. Once the ceiling is set, the Congressional appropriations committees are obliged to make the budgets of the government departments they handle fit under it.

This year, for example, the House Budget Committee recommended $127.4 billion for national defense. Rep. Samuel S. Stratton (D-N.Y.) argued that the recommended ceiling was too low; that it should be raised by $2.4 billion to $129.8 billion. The whole House on May 3 voted 262 to 142 against the Stratton add-on after hearing this plea from Chairman Robert N. Giaimo (D-Conn.) of its Budget Committee:

"By holding the line on spending add-ons, whether they be in defense or in other areas of the federal budget, we will begin to get some discipline on spending." Giaimo added that the $2.4-billion Stratton wanted to add would go for another nuclear aircraft carrier, which the House had voted down last year.

Despite the House vote to hold the line, its Armed Services Committee decided to ignore it by sending to the floor a defense money bill that would require the higher ceiling Stratton had vainly sought. The committee's rewrite of the president's defense program was assailed by its critics within the House as the biggest Christmas tree yet, loaded with goodies for the aerospace contractors and the Air National Guard.

"The Committee on Armed Services ran amok this year in markup," charged Rep. Bob Carr (D-Mich.) in a floor speech. "The authorization bill is not a national security bill. It is a political security bill" because of all the money added for planes and other weapons built in the home states of the committee members.

It was against that backdrop that Schroeder, feeling out of sync dressed in khaki with military insignia, delivered her warning about the Armed Services Committee's marching into obsolescence.

"We have gotten ourselves into a box by adopting legislation that authorizes the Committee on the Budget to set the budget," she said. "We have all voted on putting the lid on ourselves. We as a committee have to take much more cognizance of the lid, or we as a committee have really become rather useless."

If the committee persists in ignoring the lid imposed by the full House upon recommendation of its Budget Committer, she continued, "What we would do is end up being a menu-providing services, a situation in which we could provide the largest possible menu to the the Committee on Appropriations and to the Committee on the Budget to whack away at. I think we will have lost a lot of our effectiveness if we do that."

Besides its recommendations degenerating to the status of a restaurant menu by failing to make the hard choices to come under the budget ceiling, Schroeder continued, the House Armed Services Committee will, if it does not learn fiscal discipline, "hurt national defense.

If the House Armed Service Committee leaves it to the Appropriations Committee to do all the cutting needed to get the Pentagon money bill under the ceiling, she reasoned, what will get slashed is the non-glamorous operations and maintenance account - the money to keep ships, planes and tanks in good repair. Ships, for instance, that are run ragged force crews to work around the clock once they reach port - a factor in the Navy's record-high desertions.

"Whom do we know who is around here lobbying for readiness versus whom we know around here lobbying for hardware?" Schroeder asked her colleagues. "I do not know of anybody who belongs to the readiness lobby. I know a lot of persons who belong to Grumman and other people like that who happen to be selling hardware. That is why I fault the committee for giving us much too big a menu of hardware.

Despite her pleadings, the House rejected the slimmer Carter administration defense bill Schroeder and her allies championed by a vote of 287 to 115. The Christmas tree stayed up. And if Schroeder is right, the House Armed Services Committee will soon be as believable to adults as Santa Claus.