For people who claim that defaulting on U.S. debt is unthinkable, President Obama and Harry Reid are sure behaving as if they can't wait for that day to arrive. Why else are they refusing to take up the multiple Republican offers to guarantee that the U.S. will never default?

Treasury Secretary Jack Lew now says his department can't be sure it will have enough cash to guarantee interest payments after October 17, and he is raising alarms about a default catastrophe. Mr. Obama declared again on Wednesday that he'll only negotiate...