A proposed change in tax laws that was intended to give religious leaders more freedom to engage in partisan politics appeared to be losing support in Congress yesterday after it came under fire from both liberal and conservative religious groups.

The Southern Baptist Convention, which supports the broad goal of the legislation, sent House members a letter opposing the specific language that House Republican leaders last week tacked onto a major tax bill, the American Jobs Creation Act of 2004.

The Rev. Richard D. Land, head of the convention's Ethics and Religious Liberty Commission, said the language is "loose enough that it could be interpreted to broaden the restrictions" on political speech by clergy members, rather than loosening them. "This is a case in which the cure is worse than the disease," Land said.

The provision also was attacked by the Interfaith Alliance, a coalition of liberal church groups, and by Americans United for Separation of Church and State. They said it appeared to be an attempt to help President Bush's election campaign and to chip away at the First Amendment's prohibition on an establishment of religion.

A spokesman for House Speaker J. Dennis Hastert (R-Ill.) said the provision was intended to "meet the concerns" of Rep. Walter B. Jones Jr. (R-N.C.), who has pushed for years for a law to allow clergy members to endorse political candidates from the pulpit. Mike Stokke, Hastert's deputy chief of staff, said the speaker's office had heard from a growing number of clergy who questioned the specifics of the proposal.

Jones's chief of staff, Glen Downs, said the congressman does not support the language written by the Ways and Means Committee staff and is trying to change it. Downs said the bill could increase Internal Revenue Service scrutiny of churches by creating a graduated set of penalties for violating the rules on political activity.

At present, he said, the IRS must make an "all or nothing" decision: either strip a church's tax exemption or leave it alone.