More than 86 percent of the U.S. Capitol Police force, citing low pay, high turnover and dwindling morale, is seeking union representation by the Fraternal Order of Police after 158 years without a labor representative.

Except for cost-of-living increases, Capitol Police, who are responsible for patrolling a 40-block area around the Capitol and protecting it against possible terrorist attacks, have not had a pay raise since 1972, and one 15-year veteran said morale is "so low you can sweep it up off the ground."

According to Sgt. Mike Yohn, cochairman of the FOP's newly established Capitol Police Labor Committee, 980 officers and officials of the 1,135-member force in a four-day period signed petition cards indicating that they wanted to be represented by the FOP.

Because congressional employes are exempted from many federal labor laws, legislation is being sought to allow the Capitol Police, who are employes of the House of Representatives, to organize.

Reps. Mario Biaggi (D-N.Y.) and Stan Parris (R-Va.) are supporting efforts to recognize formally the force's right to have a bargaining agent. Employes of the Library of Congress won that right in 1978 by specifically being included in the Civil Service Reform Act, which granted collective bargaining rights to federal employes.

"We're going to go after an amendment [to the act] that says 'including Capitol Police,' " Yohn said.

Even if the Capitol Police are successful, the FOP, which represents the D.C. police, would not be able to negotiate pay and retirement benefits. Yohn said, "We would like to have a say in our jobs as far as promotions, transfers and other working conditions."

Officer Rose Bridwell, another labor committee cochairman, said, "We feel it's a crime, especially to work for Congress in the seat of democracy, not to have a say in what happens to us."

Half a dozen officers interviewed by The Washington Post, all of whom asked not to be identified, cited low pay and poor retirement benefits as the main source of discontent. The Capitol Police are among the lowest-paid law enforcement officers in the area. First-year officers are paid $18,100, compared with $21,700 for rookie D.C. police officers.

The high turnover is an indication of poor morale, Yohn said. According to Capitol Police spokesman Bob Howe, the turnover rate this year is expected to be 16.3 percent, up from 4.6 percent three years ago.

Officers who have left the force frequently mention low salaries as the reason, he said, and the department has made a pay increase an "item of priority." Howe said the department has not taken a position on the movement to organize members, adding that he thinks that the Capitol Police force is a "good place to work."

According to the officers interviewed by The Post, the force's disciplinary procedures and appeals processes are vague, and members of the force often have had to rely on informal contacts with members of Congress to resolve disputes.

Last June, a storm erupted when the new chief of the force, James J. Carvino, ordered that employes "shall not seek the influence or intervention of any person outside the force for purposes of personal preferment, advantage, transfer, advancement or to gain favor or preferential treatment of any kind."

"The purpose of the memo was simply to try to take politics out of advancements and disciplinary actions and things of that nature," Howe said. "There was no intention there to violate anyone's rights."

However, officers said they thought that Carvino was trying to bar them from talking with their representatives, and the order was clarified after Parris intervened.

Another controversy occurred when Carvino placed officers on rotating schedules that in some cases removed them from posts they had manned for more than 10 years. The order was rescinded after members of Congress complained that the new officers did not know who the legislators were, a problem that is aggravated by the force's turnover rate.

Capitol Police spokesman Howe said the order was a result of personnel shortages caused by cutbacks in the force's budget. "We were coming up shorter and shorter on personnel because we couldn't hire replacements," he said.

However, an aide to one of the members of Congress who are assisting in the organization effort had a different explanation: "The idea was that officers wouldn't be able to work at locations where they see the same congressman every day and say, 'Oh boy, guess what the chief did today.' " The aide, who did not want to be identified, said he thought the dual victories over Carvino's orders had shown members the potential of their lobbying efforts.