The Georgia Democrat told a gathering of more than 1,000 lawmakers at the American Legislative Exchange Council that Mr. Obama's effort to close the prison would "treat the terrorists as they were a run of the mill criminal instead of what they really are."
He drew more applause from the mostly Republican legislators who packed a downtown Atlanta hotel ballroom when he said Mr. Obama needed to spend more time in Washington and less time traveling abroad.
"Our globe-trotting president needs to stop and take a break and quit gallivanting around," Mr. Miller said, adding that White House Chief of Staff Rahm Emanuel needs to put "Gorilla Glue" on his chair to keep him in the Oval Office.
Two black leaders who know Mr. Miller well said they were not offended by the remark.
The Rev. Joseph Lowery, a civil rights leader, noted the glue is a brand name.
"I ignore it," he said. "I consider the source and go about my business."
Democratic State Rep. Tyrone Brooks, who leads the Georgia Association of Black Elected Officials, said he wasn't offended by Mr. Miller's comment, but said it came a few years too late.
"It would have been much more appropriate that he suggest that Karl Rove used some Gorilla Glue on George Bush and Dick Cheney," said the Atlanta Democrat.