WASHINGTON — A Washington watchdog has filed a complaint against Louisiana Democratic Sen. Mary Landrieu, suggesting she may have traded her influence on a specific earmark for $30,000 in campaign contributions. Citizens for Responsibility and Ethics in Washington on Tuesday demanded the U.S. Department of Justice and U.S. district courts in Louisiana and Texas investigate whether Landrieu, who is in her second term, broke federal law back in 2001 by including a $2 million earmark in the District of Columbia appropriations bill for a company whose lobbyists had thrown her a fundraiser just days earlier. That event, held four days...