Federal and postal employees could run for governor or manage the mayor's campaign, but he limited to voter-only roles in national political campaigns under a Hatch Act compromise advanced by a Washington area congressman that the House will consider next Thursday.

Legislation to remove all barriers to political participation by federal workers has been approved by the House Post Office-Civil Service Committee. The bill, by Rep. William Clay (D-Mo.: would open the door for the first time in 38 years for federal civil servants to become active in politics, as candidates, managers of fund raisers.

AFL-CIO federal and postal unions want the Hatch Act changes. They argue that it is unfair to deprive 2.6 million of the nations' best paid, best trained workers of full political rights just because they get a government pay check every two weeks.

The unions admit that changing the Hatch Act would permit them to take more active political roles - and make it easier for them to raise large sums of money from members for political education activities. They believe an active bureaucracy led by unions could win bigger pay and fringe benefits, and have more say in how the government is run.

Opponents of Hatch Act changes contend that it could lead to increased arm-twisting of government workers for time, money and votes, and that it could put some taxpayers in an awkward position if an influential or important "politicized" federal employee leaned on them.

Rep. Joseph L. Fisher (D-Va.), who represents more federal workers than perhaps any other member of Congress (Gladys Spellman and Herbert Harris might disagree says he favors Hatch Act changes for state and local politics, but not at the national level. Confining federal workers to active local roles would, Fisher believes, minimize pressure on them that could lead to questionable or illegal acctions.

Fisher, who must capture most of the federal employee vote in his distirct if he plans to remain in Congress, says polls have shown that his government constitutents do not favor the Hatch Act changes before Congress. Fisher says that polls conducted in Montgomery County show the same thing.

As a compromise, Fisher and some 20 House backers plan to offer a bill as an amendment to the full-freedom Hatch Act changes proposed by Rep. Clay. AFL-CIO lobbyists think they have the votes to pass the Clay bill, but they admit that Fisher's plan - which they oppose on grounds that it is only half-a-loaf - could give them trouble.