BATON ROUGE (AP) — Democratic U.S. Sen. Mary Landrieu called her opponent, Republican state Treasurer John Kennedy, a political opportunist while Kennedy painted Landrieu as an example of an ineffective Congress, as the two traded attacks Monday in their first debate of the race. The campaigns leading up to the Nov. 4 election mainly have been fought on the TV airwaves, in mass e-mails and on Web sites in increasingly negative exchanges. —- Contact The Daily Reveille’s News Staff at [email protected]