Libertarian presidential nominee Bob Barr has asked Republican Congress member Ron Paul to join his ticket as his vice-presidential nominee. Paul made a failed bid for the Republican nomination earlier this year. Barr’s request came as he refused to appear at a unity event with other third-party candidates in Washington, D.C. Barr initially pledged to attend, but backed out after citing differences with Green Party candidate Cynthia McKinney. McKinney and Paul appeared at the event Wednesday, along with Independent presidential candidate Ralph Nader and Constitution Party nominee Chuck Baldwin.