Sen. Rudy Boschwitz, R-Minn., has performed a remarkably useful service. He recently exposed billions of dollars in what are known as "add-ons and plus-ups" to the defense appropriations bill. He was talking, of course, about political pork.

Boschwitz is one of the ablest - and quietest - members of the Senate in which he has served for the past 10 years. He does his homework. He seldom speaks on the floor, and because he has small tolerance for sacred cows he is not an especially popular member of the club.On Aug. 11, he did nothing to gain him favor. He offered an amendment to strike $1.7 billion in add-ons; before the chill descended, he was prepared to offer a separate amendment to cancel $4 billion in plus-ups.

An "add-on" is an appropriation never requested by the Department of Defense. A "plus-up" is an increase over the Pentagon's proposed spending.

The senator was striking, unsuccessfully, at a pernicious practice in Congress. This is the tendency on the part of Congress not merely to set policies, but also to micromanage their execution.

"The magnitude of waste caused year in and year out by congressional pork barreling rivals - in fact dwarfs - the cost of fraud that is now being unearthed," Boschwitz said. He provided three pages of examples of unrequested spending.

One add-on provides $14.5 million to establish an "optoelectronics materials center" at an unnamed university, but when he sought to learn which university, "we were not able to get answers from the Appropriations Committee." (This reporter was unable to get answers either).

The bill adds $3 million for a study of "the cause of limited supply of minority and women scientists, engineers and technologists." How did that get in the bill? Another item calls for $60 million in unspecified development of "threat simulators." The Pentagon asked for none of these.

Neither did the Navy ask for $2 million for maintenance of a facility in San Diego. The Air Force did not request funds for hospital repairs at the Air Force Academy.

The bill adds an unsought $80 million for certain explosives, $40 million for additional Sparrow missiles, $55 million for two additional KC-130T planes for the Marine Corps Reserve, $42 million to buy six more MH-60 helicopters for the 304th Aerospace and Rescue Squadron.

The list of add-ons runs on and on: $130 million for 58 additional M-1A1 tanks, $326 million for 16 C-130 planes for the Air National Guard, $50 million for unspecified "miscellaneous equipment" for the Army National Guard. Among the plus-ups is an increase of more than $8 million to maintain two inactive ammunition plants in Illinois and Wisconsin. Many of the items mandate not only what additional materiel should be provided, but also where it should be acquired.

Boschwitz, who is not the most tactful member of the Senate, rubbed in a little salt. Many members who complain most fervently about excessive spending for defense, he said, are the same members who ask special favors for defense spending in their own states.

Louisiana's Sen. Bennett Johnston responded acidly that the Boschwitz amendment "would make Congress superfluous. If the Pentagon's requests are to be rubber-stamped, neither decreased or increased, the legislative function would be nullified."

His main point was that agreement had been reached with the White House on a figure of $299.5 billion in defense spending for the coming fiscal year. After all the cutbacks, add-ons and plus-ups, the bill was within that amount. Boschwitz's amendment would reduce the total. "What are we supposed to do?" asked Johnston. "Are we supposed not to spend the money?"

Well, perish the thought.

Boys will be boys, and the purpose of pork barrel spending is to bring home the bacon. Recognizing this political truth, Boschwitz saw that his amendment would lose by roughly 99-1 if all senators voted. He therefore withdrew his motion, but he had made his embarrassing point.