WASHINGTON (AFP) - Senator John McCain fought for the backing of the Republican Party's conservative base in a fiery speech Thursday just after rival Mitt Romney quit the race, clearing his path to the White House. Addressing the annual gathering of fervent Republican activists, McCain sought to shore up his conservative credentials and allay fears over his stand on some key issues as he seeks the party's presidential nomination. "It is my sincere hope that even if you believe I have occasionally erred in my reasoning as a fellow conservative, you will still allow that I have, in many ways...