As thousands prepare to attend Texas Gov. Rick Perry's prayer rally, The Response, opponents held an interfaith service in Houston Friday night.
Although they haven't found evidence, they've accused Perry of using tax dollars to plan the event and say he's blurring the line between church and state.
Barry Lynn, executive director of Americans United for Separation of Church and State, warned the governor "don't mess with the Constitution."
"Don't believe that just because you're the governor you have something in your job description that says you're the pastor of everyone from San Antonio to Dallas," he said.
Members of Council on American-Islamic Relations (CAIR) were also present at Friday's protest.
"If it had been a Muslim governor, head of state, and he elected to have a Muslim prayer and opposed to bringing other people in, that would have been a big issue," Mustafa Carroll of the Dallas Fort Worth Chapter of CAIR said.
"As governor I would hope he represents all of those in Texas and participating in a Christian day of prayer once again puts some of us outside that stadium," The American Jewish Committee of Houston's Randy Czarlinsky charged.
CBN News' Jennifer Wishon will have a report from The Response, U.S.A. on Monday's "The 700 Club." Check local listings. Also see her report on the CBNNewschannel.com and on CBNNews.com.