DENVER -- Four Air Force officers have joined in a lawsuit claiming senior officers and cadets at the Air Force Academy illegally imposed Christianity on others at the school.

Meanwhile, congressional opponents of proposed new guidelines on religious conduct in the Air Force have sent a letter to President Bush asking him to issue an executive order protecting the right of Christian military chaplains to mention Jesus in prayers.

A letter signed by more than 70 members of the House says "Christian military chaplains are under direct attack and that their right to pray according to their faith is in jeopardy."

The letter, written by Rep. Walter Jones, R-N.C., said, "We believe that the Air Force's suppression of religious freedom is a pervasive problem throughout our nation's armed forces" and "it is becoming increasingly difficult for Christian chaplains to use the name of Jesus when praying."

The lawsuit in U.S. District Court in Albuqerque, N.M, was filed by Mikey Weinstein, an academy graduate and former Air Force officer, who said he had failed to win an assurance from the Air Force that Christian chaplains would stop proselytizing.

Four second lieutenants, all members of the graduating class of 2004, joined the lawsuit this week, said Sam Bregman, Weinstein's lawyer. He identified them as Casey Weinstein, one of Mikey Weinsten's sons, Jason Spindler, Patrick Kucera and Ariel Kayne.

"Any argument that Mr. Weinstein didn't have standing -- that argument is over," said Bregman. Weinstein said that if Bush issues an executive order that permits chaplains to proselytize he will add the president to the list of defendants.

In addition to the letter to Bush, evangelical groups were pushing their side in meetings with top Air Force officials. Jim Backlin, vice president for legislative affairs of the Christian Coalition, said he had met with acting Air Force Secretary Pete Geren.

"I told the secretary we are concerned that the guidelines as written would have a chilling effect and are already having a chilling effect," Backlin said.

Backlin said the guidelines are unnecessary.

They were written after complaints by Weinstein and others that Christian evangelicals were aggressively proselytizing at the academy, in some cases using their official positions to advance their cause. An investigation of the academy found no overt religious discrimination but observed a lack of sensitivity among some and confusion over what is permissible in sharing one's faith.

The Air Force's chief of chaplains, Maj. Gen. Charles C. Baldwin, appears to have reservations about the guidelines. In a videotaped message sent to all chaplains he invited them to comment on the rules so the Air Force could "get this right."

Weinstein said Baldwin should be fired for advocating practices the guidelines have ruled out, including senior officers sharing their faith with their subordinates as long as it is not done coercively.