Debt crosses $14 trillion mark

NEW YORK (CNNMoney) -- The amount of U.S. debt subject to the country's legal maximum has topped $14 trillion for the first time.

On Wednesday, the amount of debt subject to the cap hit $14.001 trillion at the close of trade, according to the daily Treasury statement released on Thursday.

That means the country is less than $300 billion away from the $14.294 trillion debt ceiling, which is a cap on how much the federal government can legally borrow.

The debt ceiling has become a focal point of the debate over spending and debt. Even though congressional leaders say the cap will be raised, Republicans are vowing to use the issue as leverage to force spending cuts.

The Treasury Department estimates that borrowing could reach the cap sometime between March 31 and May 16, according to a letter Treasury Secretary Timothy Geithner sent to Congress earlier this month.

While Treasury has certain measures it can take to postpone a breach from occurring, Geithner said they would only last "several weeks."

He urged lawmakers to act soon to raise the ceiling, warning that failure to do so would be disastrous for the economy and for Americans.

Although the debt ceiling has never been reached -- so it's impossible to say definitively what would happen if it were -- budget and debt experts warn that no good can come of it.

If U.S. borrowing hits the ceiling and lawmakers fail to raise it, Treasury would be prohibited from borrowing more money. Barring immediate and draconian policy changes, the country would be unable to pay its bondholders or fund programs and benefits in full. That's because there wouldn't be enough tax revenue coming in to cover all of the country's bills.

Experts say the cascade effect would be crippling not only to the U.S. economy but very likely to economies and markets worldwide.

At a minimum, a default could pummel U.S. bonds, the dollar and U.S. investors' portfolios.