Resorting to credit has long been the American solution for dealing with expensive crises  as long as the solution has wide public support. Fighting World War II certainly had that support. Even now many Americans tolerate running up the deficit to pay for the wars in Iraq and Afghanistan, which cost $11 billion a month combined. And so far there is wide support for an initial outlay of at least $250 billion for a rescue of the financial system, if that will stabilize banks and prevent a calamitous recession.

Image The next president will inherit a fiscal and economic mess of historic proportions, said Senator Kent Conrad, chairman of the Senate Budget Committee. Credit... Tim Sloan/Agence France-Presse — Getty Images

“There are extreme circumstances when a larger national debt is accepted as the lesser of two evils,” said Robert J. Barbera, chief economist at the Investment Technology Group, a research and trading firm.

There are also assumptions that help to make America’s deficits tolerable, even logical.

One is that people all over the world are willing, even eager, to lend to the United States, confident that the world’s most powerful nation will always repay on time, whatever its current difficulties.

“So far the market is showing that it is quite willing to finance our needs,” said Stephen S. McMillin, deputy director of the White House Office of Management and Budget.

Lenders are accepting interest rates of 4 percent or less, often much less, to buy what they consider super-safe American debt in the form of Treasury securities. The 4 percent rate means that the annual cost of borrowing an extra $1 trillion is $40 billion, a modest sum in a nearly $14 trillion economy, helping to explain why the current growing deficit has encountered little political resistance so far.

But if recent history repeats itself, the deficit is likely to be an issue again when the economy recovers.