Civil libertarian and religious groups continue to fight a rear-guard action against President Reagan's appointment of an ambassador to the Holy See. But they appear to have little chance of blocking the move.
Representatives of Americans United for Separation of Church and State (AU), the Baptist Joint Committee on Public Affairs, and a number of other organizations testified at a Senate Appropriations subcomittee hearing Monday against providing funds for the establishment of a US embassy at the Vatican. The State Department has made a request to ''reprogram'' $351,000 of its funds to upgrade the Vatican mission.
Both the House and the Senate appropriations panels have yet to act on the request. But, in the absence of broad-based and vocal public opposition to the establishment of formal ties with the Vatican, it is likely the vote will be favorable, congressional sources say. Earlier this month, the Senate Foreign Relations Committee overwhelmingly approved the nomination of William Wilson to be the first US envoy to the Holy See. The full Senate must now vote on the matter.
''We recognize that it's an uphill battle,'' a spokesman for AU said following this week's hearing, ''and we want to make sure our points are made on the Hill. But it looks as if the majority (of the appropriations subommittee members) do not see it our way.''
If the Senate confirms the Wilson appointment, and the appropriations panels approve funds for an embassy, opponents of the move plan to pursue the issue in the courts. An official of AU said the organization's lawyers are now working on how to present the case. But he added that recent judicial decisions suggest the US Supreme Court has become more flexible on the issue of church-state separation.
In their statements before the Senate appropriations panel, various religious and libertarian groups made these points:
* The United States is sending an ambassador not to a ''state,'' i.e., Vatican City, but to the Holy See, the governing structure of the Roman Catholic Church.
* This gives favored status to one church over others and violates the establishment-of-religion clause of the Constitution.
* The fact that 107 other nations have full diplomatic ties with the Vatican is irrelevant, because the US is unique in its constitutional provision for church-state separation.
* The move could rekindle religious divisiveness after a period of increased ecumenical harmony.
* Establishment of formal relations with the Holy See would permit the US President to become entangled in the internal affairs of the Catholic Church - by seeking, for example, to influence church policy on such issues as a nuclear freeze.
* The congressional legislation removing the 1867 ban on the use of federal funds for a mission at the Vatican was passed without prior public hearings and only by a voice vote.
* The State Department's ''reprogramming'' request is questionable since the procedure was not intended to allow introduction of new and controversial programs.
The State Department position is that formal diplomatic relations with the Holy See will give the US greater access to the church's vast intelligence network and enable it to try to influence the church's political positions. Secretary of State George P. Shultz is expected to be questioned on the issue when he appears before the Senate appropriations panel March 28.
Hearings were held in the Senate subcommittee at the initiative of Senators Mark O. Hatfield (R) of Oregon and Lowell P.Weicker (R) of Connecticut, who felt that opponents of funding for an embassy at the Vatican should be given opportunity to state their views. They themselves are opposed to diplomatic recognition of the Vatican and are expected to vote against a reprogramming of funds for an embassy.