(CNN) - Prominent liberal groups and gay rights proponents criticized President-elect Barack Obama Wednesday for choosing evangelical pastor Rick Warren to deliver the invocation at the presidential inauguration next month.
Warren, one of the most powerful religious leaders in the nation, has championed issues such as calling for the reduction of global poverty, human rights abuses, and the AIDS epidemic.
But the founder of the Saddleback Church in Lake Forest, California, has also adhered to socially conservative stances - including his opposition to gay marriage and abortion rights that puts him at odds with many in the Democratic Party, especially the party's most liberal wing.
"[It's] shrewd politics, but if anyone is under any illusion that Obama is interested in advancing gay equality, they should probably sober up now," Andrew Sullivan wrote on the Atlantic Web site Wednesday.
People for the American Way President Kathryn Kolbert told CNN she is "deeply disappointed" with the choice of Warren, and said the powerful platform at the inauguration should instead have been given to someone who is "consistent mainstream American values.
"There is no substantive difference between Rick Warren and James Dobson," Kolbert said. "The only difference is tone. His tone is moderate, but his ideas are radical."
Dobson, a social conservative leader, is founder and chairman of Focus on the Family.
Linda Douglass, a spokeswoman for Obama, defended the choice of Warren, saying, "This is going to be the most inclusive, open, accessible inauguration in American history."
"The president-elect certainly disagrees with him on [Lesbian, Gay, Bisexual, Transgender] issues. But it has always been his goal to find common ground with people with whom you may disagree on some issues."
Douglass also noted Obama and Warren agree on several issues including advocating on behalf of the poor and the disadvantaged, and people who suffer from HIV/AIDS.