WASHINGTON — Washington loves a whodunit. And the latest one comes with the stunning plot twist of a leak from the famously buttoned-up Supreme Court.The publication this past week of a draft opinion that said Roe v. Wade, the landmark 1973 decision establishing a constitutional right to abortion in the United States, was wrong from the start and should be overruled, has set off sleuthing from every corner of the capital.Who could possibly be behind such a glaring breach of trust? Why did that person choose to leak …