But behind the scenes, Treasury Secretary Timothy F. Geithner has already begun juggling the books to conserve cash, draining a special account at the Federal Reserve. And with the debt forecast to hit the legal limit of $14.3 trillion in just a few weeks, he has a range of tools at his disposal, including borrowing money from a pension fund for federal workers.

Geithner also has authority to pay investors first for interest they’re owed on the debt, according to a decades-old legal opinion. A growing number of conservatives argue that by making interest payments first, the government could avoid default and the Obama administration’s predictions of economic Armageddon.

But the nation could pay a substantial price in the form of higher interest rates if it relied for long on such evasive maneuvers, the Government Accountability Office said in a recent study. And financial analysts say market confidence could be shattered if Geithner had to cut off pay to combat troops or stop writing Social Security checks — even if he never missed an interest payment.