A U.S. Court of Appeals panel has ruled that a lower-court judge acted prematurely when he decided that the Hatch Act prohibits federal employe unions that endorse political candidates from conducting voter registration drives.

The panel, in a 2-to-1 decision Friday, said neither the unions nor the government is entitled to the action they seek because the matter "is not ripe for judicial review."

The panel returned the case to the lower court with instructions to dismiss the complaints.

U.S. District Court Judge Thomas P. Jackson, in a July ruling, affirmed an earlier decision by K. William O'Connor, special counsel to the Merit Systems Protection Board, whose office enforces the Hatch Act.

In March, O'Connor told the American Federation of Government Employes and the National Treasury Employes Union that they lost their right to register voters when they endorsed Democrat Walter F. Mondale for president.

O'Connor said the Hatch Act permits unions to conduct registration drives and to endorse candidates, but not both. Once a union endorses a candidate, he said, it becomes "a partisan club for the duration of the campaign" and is prohibited from engaging in voter drives.

The appeals court, in a decision written by Judge Ruth Bader Ginsburg, said the unions "have framed a general question not wedded to the facts of a particular case."

Ginsburg said O'Connor, as special counsel, may investigate, prosecute and extend advice, but not judge Hatch Act liability. That power rests with the MSPB, she said.