Senate Majority Leader Bill Frist has muddled the constitutional separation of church and state by joining with conservative Christian leaders in a campaign aimed at “reining in our out-of-control courts.”

That phrase is from a Family Research Council announcement of a huge nationwide televised protest rally called “Justice Sunday” on the evening of April 24. Dr. Frist (a medical doctor) has agreed to join some of the nation’s most influential conservative Protestants on the program. They include Dr. James C. Dobson, founder of Focus on the Family; Dr. Al Mohler, president of the Southern Baptist Theological Seminary, and Chuck Colson, a Nixon aide who served prison time for his part in the Watergate scandal and later became a prison evangelism leader.

Organizers hope to reach more than a million people by distributing the telecast to churches across the country and over the Internet and Christian television and radio networks and stations.

Their immediate target is the filibuster, the Senate device that can be used to require 60 votes rather than a simple majority of 51 to bring an issue to the floor for a vote. They charge that it is used “against people of faith.” Democrats used it to block 10 of President Bush’s judicial nominations in the last Congress. Ninety-five percent of his 214 first-term nominees were approved. In President Clinton’s first term, the Republican-controlled Senate blocked 35 percent of his circuit court nominees.

An invitation letter by the Family Research Council’s president, Tony Perkins, attacked the courts as “the last great bastion of liberalism.” He blamed court decisions for changing the nation’s course, “whether it was the legalization of abortion, the banning of school prayer, the expulsion of the Ten Commandments from public spaces, or the starvation of Terri Schiavo.”

Dr. Frist signed on with this religious-political campaign after seeing a dwindling possibility that he could round up the necessary 51 votes for his threatened parliamentary maneuver to rule out the filibuster in cases of judicial nominations. Some observers suspect that, as a likely candidate for the 2008 Republican presidential nomination, he hopes to inherit the backing of the extreme religious right, which helped Mr. Bush’s 2004 re-election campaign.

But whatever the reach of his political motives, Dr. Frist ventures onto shaky constitutional ground in joining with zealots who seek to restrict and punish judges when they disagree with their decisions. He had joined with President Bush in distancing himself from Tom DeLay, the House majority leader, when Mr. DeLay threatened to discipline the judges who blocked legislative intervention in the Schiavo case. Now Dr. Frist is beginning to sound like Mr. DeLay.

He may also be making a political mistake. Opinion polls show that most Americans respect their country’s independent judiciary and that a majority opposed congressional and presidential intervention in the Schiavo case. The religious right may have been given too much credit for the Republican victories in 2004. They are certainly overstepping reasonable bounds in this new attack on the independent U.S. court system.