SHOULD THE FEDERAL government be a collection agent, passing the hat among employees for contributions to clearly political groups? The administration doesn't think so, and neither do we; but on Friday, U.S. District Judge Joyce Hens Green ruled that a Reagan administration order barring legal defense funds and other political and lobbying groups from participating in the government's one-fund charity campaign is unconstitutional. For practical, philosophical and legal reasons, we believe the government should appeal.

It is not a question of what groups are worthy of contributions from individual employees of the government; how they do or don't give money to charities is their private business. But when it comes to the annual one-fund campaign in government--the Combined Federal Campaign--taxpayers are footing the bill, in terms of government staff time contributed to organize and administer the campaign, to solicit and keep track of contributions and to handle payroll deduction procedures.

The original, practical idea behind this effort was to coordinate giving to voluntary organizations directly involved in health and welfare activities--not groups devoted to changing public policy or testing it in the courtroom. Last year, when the Combined Fund was open to all sorts of other nonprofit organizations-- such as the National Right to Work Legal Defense Foundation, the Puerto Rican Legal Defense and Education Fund and the Lawyers Committee for Civil Rights--the number of employee donors dropped, and various unions boycotted, cutting the money for the health and welfare agencies that traditionally benefit from the United Way and CFC efforts.

There may be many political advocacy groups that federal employees are pleased to support. But they are free to contribute to them anyway. The prohibition would mean merely that taxpayers would not have to underwrite a government fund- raising channel for this kind of hat-passing. The distinction--an important one--is between campaigns for health and welfare groups and, as described by the administration "any organization that seeks to influence elections or public policy determinations through political activity or advocacy, lobbying or litigation on behalf of parties other than itself."

Judge Green concluded that "it is firmly settled that under our Constitution public expression of ideas may not be prohibited merely because the ideas are themselves offensive to some of their hearers," and she termed the administration ruling a violation of the First Amendment rights of the defense funds. But the political ideas themselves are not the main issue; the groups represent all sorts of views. And it's not a matter of stifling the expression of ideas. At issue is whether any of these organizations have a "right" to use government time, effort, bulletin board space and payrolls to raise money for their operations. Another court may well conclude that they do not.