According to Harold Camping, May 21, 2011, was supposed to be Judgment Day. It was, in a sense. As the day came and went, the world judged Mr. Camping’s 15 minutes of fame were up. Treasury Secretary Timothy F. Geithner may yet learn something from Mr. Camping.

Mr. Geithner has been a whirlwind of worry about the nation defaulting if Congress fails to raise the debt ceiling. He has likened it to a financial judgment day, an event so terrible and unpredictable it shouldn’t be contemplated, let alone risked. Yet the market for U.S. debt — where the default would occur — remains sanguine about the debt ceiling and apparently dismissive of Mr. Geithner’s preaching. Notice, for example, how the bellwether 10-year Treasury bond rate has recently plunged to or below 3 percent, hardly a harbinger of trouble.

The markets know — as does Mr. Geithner, his protests notwithstanding — that the Treasury will not default on the federal debt. No matter what happens with the debt ceiling, interest will be paid out of ample tax revenues. Mr. Geithner knows it. The markets know it.

Debt markets also know the United States cannot continue to rack up trillion-dollar budget deficits. The long-run fiscal picture has long been disastrous, but President Obama’s policies have now nailed that long-run picture to a near-term frame, and it hangs outside the Treasury secretary’s door.

The markets are watching, not whether the debt ceiling increases, but whether Washington will let the moment pass without taking strong action on the deficits. This point was hammered home in a statement by Moody’s, the credit-rating agency, on the outlook for the rating of U.S. debt: A credible agreement on substantial debt reduction would support a continued stable outlook; lack of such an agreement could prompt Moody’s to change its outlook to negative on the “Aaa” rating.

It can’t get much plainer than that. Make real progress, or there will be a price to pay.

In contrast, Mr. Obama earlier demanded Congress pass a “clean debt ceiling,” i.e., a debt-ceiling increase devoid of extraneous matters such as spending reductions. Mr. Obama demanded Congress do the very thing markets insist must not be done — ignore the deficits. Thankfully, the House thrashed the idea, 319-97.

This follows another major Obama misstep — his budget — which continued his do-nothing, debt-based fiscal policy. The Senate repudiated the Obama budget even more resoundingly than the House did his “clean” debt-ceiling proposal. Mr. Obama’s budget got nary a vote. Neither duty nor responsibility nor shame could compel Senate Democrats to advance their own plan, but they knew they opposed the president’s.

If the debt ceiling remains as is, then wrenching changes in federal spending will follow. Mr. Obama will be forced to prioritize spending with little or no statutory guidance. In effect, Congress will have written a $2.2 trillion blank check and told the president to spend it.

“Winging it” is no way to govern. Those in Congress who oppose any increase in the debt ceiling and thus balance the budget immediately should offer their detailed plans as to how the president should spend the $2.2 trillion available. However, if Congress raises the debt ceiling, it also must force substantial reductions in federal spending to ensure immediate and lasting reductions in federal borrowing.

The markets are watching. If Washington disappoints, the consequences could be sharp and painful, not just to the budget, but to the economy — and soon.

This is about the debt we leave to future generations. It also is about the state of our economy today. If credit markets begin to price in the risk of continued profligacy through higher interest rates, then the effects on jobs will not be pretty. It will lead to a judgment day of another sort for those responsible — a very painful Election Day.

J.D. Foster is the Norman B. Ture Senior Fellow in the Economics of Fiscal Policy in the Thomas A. Roe Institute for Economic Policy Studies at the Heritage Foundation