It's a question I've often asked myself: Where are the feds when police overstep the bounds in peaceful protests?

WASHINGTON -- The United Nations envoy for freedom of expression is drafting an official communication to the U.S. government demanding to know why federal officials are not protecting the rights of Occupy demonstrators whose protests are being disbanded -- sometimes violently -- by local authorities.

Frank La Rue, who serves as the U.N. "special rapporteur" for the protection of free expression, told HuffPost in an interview that the crackdowns against Occupy protesters appear to be violating their human and constitutional rights.

"I believe in city ordinances and I believe in maintaining urban order," he said Thursday. "But on the other hand I also believe that the state -- in this case the federal state -- has an obligation to protect and promote human rights."

"If I were going to pit a city ordinance against human rights, I would always take human rights," he continued.

La Rue, a longtime Guatemalan human rights activist who has held his U.N. post for three years, said it's clear to him that the protesters have a right to occupy public spaces "as long as that doesn't severely affect the rights of others."

In moments of crisis, governments often default to a forceful response instead of a dialogue, he said -- but that's a mistake.

"Citizens have the right to dissent with the authorities, and there's no need to use public force to silence that dissension," he said.

"One of the principles is proportionality," La Rue said. "The use of police force is legitimate to maintain public order -- but there has to be a danger of real harm, a clear and present danger. And second, there has to be a proportionality of the force employed to prevent a real danger."