By Gabriella Borter and Costas Pitas WASHINGTON (Reuters) -Thousands of abortion rights supporters rallied across the United States on Saturday, angered by the prospect that the Supreme Court may soon overturn the landmark Roe v. Wade decision that legalized abortion nationwide a half century ago. The protests kicked off what organizers predict will be a “summer of rage” ignited by the May 2 disclosure of a draft opinion showing the court’s conservative majority ready to reverse the 1973 ruling that established a woman’s constitutional right to terminate her pregnancy. The court’s final ruling…