As we move slowly toward an answer to the question of the year, whether Donald Trump will have enough delegates to obtain the Republican nomination on the first ballot at the Cleveland convention in July, it is important to understand just exactly what a “contested convention” (meaning one where no one arrives as the clear nominee of the party) would mean.

For one thing, we will likely not know precisely whether Trump has the votes on the first ballot until the roll is called. Trump will undoubtedly claim he does. But we will not know whether he is bluffing because of the possibility that he will not arrive in Cleveland with 1,237 delegates who are bound by law and party rules to vote for him.