Now that the Treasury Department has nixed the odd idea of issuing a platinum coin to get around the federal debt limit, Congress once again will be forced to decide whether to raise the debt limit.

When this issue last loomed in 2011, we looked deeply at the question of whether the United States had ever defaulted before. (Answer: It is not entirely unprecedented. There are three instances when the United States could be seen to have defaulted on its obligations — in 1790, in 1933 and in 1971.)

The debt limit covers both publicly-held debt and debts the United States owes to itself (bonds to Social Security and Medicare for future obligations) so no matter what happens, the debt limit will have to be raised, one way or the other....