A Democratic lawmaker resigned on Tuesday, becoming the third member of the US House of Representatives to step down in just over a week as a wave of ethics scandals engulfs Congress.Sheila Cherfilus-McCormick of Florida announced her immediate resignation ahead of a scheduled disciplinary hearing by the House Ethics Committee, which had been weighing potential sanctions over a string of campaign finance violations.Her departure follows the recent resignations of Democrat Eric Swalwell and...