Texas religious leaders and civil liberties groups have urged Gov. Rick Perry to cut his ties to The Response, a prayer event scheduled in Houston this weekend. The Anti-Defamation League issued a statement signed by more than 50 leaders in the Houston area, the Houston Chronicle reported. The signatories included Christian, Jewish and Muslim clergy. The Rev. William Lawson, pastor emeritus of the Wheeler Avenue Baptist Church, not only signed the ADL statement but plans to speak Friday at a \"family, faith and freedom rally\" sponsored by Americans United for Separation of Church and State and the American Civil Liberties Union of Texas. \"Governor Perry has a constitutional duty to treat all Texans equally, regardless of race, religion or ethnicity,\" the ADL statement said. \"His official involvement with The Response, at minimum, violates the spirit of that duty.\" The Response, a seven-hour event, is to be held at Reliant Stadium Saturday. Perry invited his colleagues from the other 49 states but only Gov. Sam Brownback of Kansas said he would attend, and newspapers in Kansas say he may have changed his mind.