WASHINGTON — If there’s one thing Republicans and Democrats can agree on when it comes to guns, it’s their proclaimed respect for the Second Amendment.Ah, but then there’s the trickier matter of what they think those 27 words mean.Lawyers, scholars, judges, politicians and ordinary Americans have been puzzling over that question for much of two centuries.And so it is that Donald Trump and Hillary Clinton can both pledge fealty to the same sentence in the Constitution’s Bill of Rights yet still …