The issue of the Hatch Act and the potential of 2.6 million politically active federal workers has apparently been chopped from the Senate calendar of things to do in 1977.

Opposition from the chairman of the Government Affairs Committee, the threat of a year-end filibuster and lukewarm White House support have teamed up to put temporarily the lid on legal changes that would have allowed government workers to politick, raise money or run as candidates for the first time in nearly four decades.

Federal and postal union leaders, who have led the AFL-CIO backed fight for changes in the Hatch Act, got a jolt yesterday when Chairman Abraham Ribicoff (D-Conn) said he opposes the legislation and will not manage it when - and if - it comes a Senate vote. They had tried, to coax the influential senator into an if-you-can't say something-nice - please-don't-say-anything-at-all position. He did, however, say something and it wasn't nice, from the union standpoint.

Ribicoff told, a Senate hearing that he wouldn't try to bottle up the bill because he feels "every significant piece of legislation" should be acted on. He said he would complete hearings, and permit the committee to draft a bill favored by the majority. But he said he will vote against it and would ask another member of the committee (probably Sen. James Sasser of Tennessee) to manage the bill when it comes to the Senate floor.

Meantime, both the American Postal Workers Union and the National Association of Letter Carriers - two of the most potent federal worker lobby groups - have decided to postphone a joint legislative conference they had planned for fall. Main purpose of the session was to whip up Senate votes for the bill, but insiders now feel the vote won't come until January or February of next year.

Ribicoff's opposition to Hatch Act revision isn't a surprise. He voted against it last year. But his statement still has a negative psychological impact on forces pushing for expanded political rights for government workers.

"It hasn't been this bad since Common Cause came out against the Hatch Act," a union official said, "and gave it a black eye with the liberals."

Although Ribicoff said he wouldn't block action on the Hatch Act revision one doesn't have to be too deeply versed in Capitol Hill realities to know that junior committee members don't go out of their way to irritate the chairman.

If - as it appears - Hatch Act reform goes over into 1978 it could further complicate the picture for organized labor which is pushing the legislation. Many Republicans argue that the Hatch Act changes are being pushed by the Democrats because they, the Democrats, feel they have the hearts, minds, votes and potential campaign contributions of the bureaucracy in their pocket.

Throwing the Hatch Act issue over into an election year could raise new fears from politicians who are worried about the potential impact of 2.8 million government workers on the electoral process. And, if relations between the White House and organized government employees erode, it could be that President Carter, the boss, might become reluctant to hand over more political leverage to these 2.6 million workers.