Washington — A special session on scholars and visa troubles at the annual meeting here of the American Historical Association featured a speaker who wouldn’t have been able to attend last year.

Waskar T. Ari Chachaki, a Bolivian scholar who had been hired by the University of Nebraska at Lincoln but was denied a visa by the Department of Homeland Security, appeared on the panel on Friday to talk about his experience.

Mr. Ari, who was hired by the University of Nebraska in 2005 after receiving a Ph.D. in history from Georgetown University, was denied a visa after making a brief visit home to Bolivia. The university kept the job open for him, and then sued the Department of Homeland Security in March 2007. His visa was granted in July without any explanation by the U.S. government.

At the historical association’s meeting, Mr. Ari told the audience that the case had made it hard for him to make any comments on his area of study, which is Latin America, for fear it would be taken the wrong way and used against him. “I’m afraid I can’t go back to my work” on Latin America, he said.

The AHA and its 2007 president, Barbara S. Weinstein, were outspoken on behalf of Mr. Ari’s visa plight as it wound its way through diplomatic channels and the courts. —Karen Winkler and Richard Byrne