President Obama today formally barred registered federal lobbyists from serving on federal agency boards and commissions.

The move finalizes what already has been in practice following an executive order in the early days of his administration. Last September, he announced that his administration "aspired" to keep advisory boards free of federally registered lobbyists.

Since then, Obama said today in a memo to heads of executive departments and agencies that "many departments and agencies are making this aspiration a reality by no longer placing federally registered lobbyists on advisory boards -- a practice that I am now establishing as the official policy of my administration."

He instructed those department and agency heads not to make any new appointments or reappointments of federally registered lobbyists "to advisory committees and other boards and commissions."

"My administration is committed to reducing the undue influence of special interests that for too long has shaped the national agenda and drowned out the voices of ordinary American," Obama said in his memo.

Click here to read the executive order.