WASHINGTON D.C., December 6 (CNA) .- A religious liberty expert is concerned that the U.S. State Department appears to be collaborating with a group that has worked to outlaw criticism of Islam around the world.

"The U.S. government should not be getting into the business of trying to shape what people say about religion," said Paul Marshall, senior fellow at the Hudson Institute's Center for Religious Freedom.

Marshall made his remarks to CNA on Dec. 5, after Secretary of State Hillary Clinton invited the Saudi Arabia-based Organization of Islamic Cooperation to attend a Dec. 12-14 conference in Washington, D.C. to build "muscles of respect and empathy and tolerance."

In Marshall's view, Americans should be "very concerned" that Clinton and the State Department "are taking the organization seriously."

He explained that the Organization of Islamic Cooperation has explicitly campaigned against free speech for years, pushing resolutions at the United Nations to ban anti-Islamic speech. The group has also worked for more than two decades to encourage states to ban speech that is insulting to Islam and to punish "Islamophobia."

In a Dec. 5 opinion article in The Wall Street Journal, Marshall joined Nina Shea, also a senior fellow at the Center for Religious Freedom, to raise concerns about the upcoming conference.

Marshall said that preparations for the conference are vague enough that questions about what it will entail are going unanswered. He noted that the conference has not been officially announced and a list of its participants and schedule has not been released.

There is very little chance that the United States will adopt the speech-limiting legislation proposed by the organization, which blatantly violates the First Amendment, said Marshall.

However, the conference could still be influential because the U.S. government exercises substantial power through the State Department's diplomatic channels and its funding of various groups.

Clinton's invitation, Marshall said, "raises expectations" that the Obama administration will cooperate with the Organization of Islamic Cooperation, which could lead to an increase in self-censorship.

Marshall described the appearance of cooperation with such a group as "demoralizing" to those people in the Muslim world who have suffered because they were accused of insulting Islam.

Holding this conference is "sending exactly the wrong message" to the world, he argued.

Instead, the United States should be vigorously "defending free speech," upholding the "unique stance" that it has traditionally held on the subject, he said.