Bishop Gene Robinson of New Hampshire, the nation's first openly gay Episcopal bishop, has given his endorsement to presidential hopeful Barack Obama, citing the Illinois Democrat's experience with racism and discrimination.

Obama's campaign put out a news release announcing Robinson’s support. It identified Robinson as "a civil rights leader and a leading voice in the faith community."

The bishop says he hopes to persuade Obama to embrace same-sex marriage. Obama supports civil unions and rights for gay couples, but stops short of supporting gay marriage.

The Washington Post reported that three hours after the announcement, Welton Gaddy, president of the Interfaith Alliance, said it was "just the latest example of candidates misusing religious leaders for political gain."

Gaddy said he was sending a letter to all the presidential candidates asking them not to make endorsements that appear to be speaking on behalf of their house of worship or denomination.

"In recent presidential campaigns little concern has been in evidence about the negative consequences that certain political strategies bring about for houses of worship," Gaddy's letter reads.