We begin with breaking news that affects every american tonight. America's top credit rating is officially on the line. A major agency now threatening a downgrade, lowering america's sterling... See More
We begin with breaking news that affects every american tonight. America's top credit rating is officially on the line. A major agency now threatening a downgrade, lowering america's sterling financial status in the world. And all because hard line members of congress have brought the u.S. To the brink. So, what does this mean for a frustrated nation tonight? We have two reports, starting with abc's chief business correspondent, rebecca jarvis. Reporter: It is a warning shot to the nation. Fitch, one of the major agencies that judges america's financial health, saying tonight that america's aaa credit, among the best in the world, is now in danger of being lowered because the political brinkman ship could increase the risk of a u.S. Default. A startling warning that, because of the showdown in washington, america may not be able to pay what it owes. The deadline is looming. Rating agencies are talking about downgrading us as early as tonight. Again. Reporter: Two years ago, when one of the big agencies downgraded america, it triggered one of the worst days for your money in wall street's history. The dow plummeting 635 points. A 401(k) WORTH $100,000, LOSING Nearly $6,000 in just one day. Analysts say even if this time around, america escapes its mess without a downgrade, the u.S. Still facing serious issues ahead. Without a deal this week, experts warn of a domino effect. Not just the dow plunging, but higher interest rates, more expensive mortgages and car loans. Consumer spending less, leading to job loss. What happens thursday if there is no deal? Thursday is going to be something that we've never experienced before. If there is no deal, we will see significant pressure on our markets. Reporter: Selling? Absolutely. Reporter: Think of it like this. America is now on probation. Put there by one of the main watchdogs that tells the world whether it's safe to own our debt. The nation can be taken off probation, but his or theically speaking, these sorts of negative watches, they lead to down grades, which can be very painful and costly for the country, diane. How long before they make up their mind? Reporter: It could be as many as 90 days or we could be here in three days with a decision. It could happen that fast? Reporter: It could happen that fast. All right, rebecca, thank you.
This transcript has been automatically generated and may not be 100% accurate.