May 26, 2010  -- The U.S. national debt has passed the $13 trillion mark, according to USDebtClock.org, an independent website that tracks the real-time growth of U.S. revenues and spending.

On Tuesday, the national debt stood at $12,995,779,490,444.52, according to the Treasury Department's national debt-tracking website TreasuryDirect.gov.

The Treasury Department did not immediately return a request from ABC News for comment.

Senate Minority Leader Mitch McConnell, R-Ky., wasted no time in sounding an alarm about the new debt milestone. In a statement released today, McConnell cited the debt in his criticism of what's called the tax extenders bill, which would extend unemployment benefits and the amount of time unemployed workers could stay on their group health plan through COBRA, as well as certain tax cuts. McConnell said the bill would cost $130 billion.

"As early as today, we'll reach a dubious milestone in America: a $13 trillion national debt -- the first time in history we've crossed this frightening threshold. This extenders bill would add another $130 billion on top of that. ...This is fiscal recklessness.

"The true emergency here is our national debt," he said.

Addison Wiggin, the executive producer of the 2008 documentary I.O.U.S.A. and the editorial director of the website Daily Reckoning, said everything from the government's regular operations to the wars in Iraq and Afghanistan to the U.S. stimulus package to lackluster tax revenues have contributed to the recent rapid growth of the national debt.

A decade ago, he said, the national debt was $5.7 trillion. By 2005, it rose to $7.7 trillion. As of six months ago, it stood at $12 trillion. The larger the debt grows, the faster the U.S. government's interest payments pile up, which helps explain why USDebtClock.org's national debt tracker jumps hundreds of thousands of dollars in less than a minute.

"As time goes on, it's such a large figure, you can actually see the interest that we have to pay on it rise if you calculate it down to the second as this site does," Wiggin said.

Wiggin said that U.S. government's borrowing grew especially quickly during the height of the financial crisis, because investors wanted to lend money to the United States -- it was seen as a safer place to stash wealth than the stock market or even banks. The clamor for U.S. Treasury bonds meant that the government could negotiate lower interest rate payments on its debt.

"It's an odd catch-22," Wiggin said. "When there's crisis, people are willing to give money to the government, which allows [government officials] to finance extreme deficits, which they're then using to paper over the crisis."

Peter Morici, a University of Maryland business professor and a critic of the Obama administration's approach to the debt, said that the current debt situation can be traced back to President Reagan's era and can be blamed on the philosophies of both political parties.

"The Republican concept is if you cut taxes, miraculously revenues always appear to cover expenditures," he said. "Democrats believe they can spend whatever they want and anything that smacks of 'we're spending too much, the government is inefficient,' is some sort of heresy."

Morici warned that if the debt grows to about 150 percent of the gross domestic product -- the debt is about 90 percent of GDP right now -- the country will risk hyperinflation or "the Chinese buying up Wall Street," he said, referring to China's status as the U.S.'s greatest lender.

"Either way, we lose our financial situation in the world," he said.

But Wiggin believes there's hope. In the World War II era, he said, the country faced a national debt that was 125 percent of the GDP.

"After World War II, as a nation, we buckled down and paid off a large portion of the debt," he said. "I'd say there's always hope because we have done it before."

ABC News' Matthew Jaffe contributed to this report.