The United States' Medium Term Challenges Rating

That meant despite the 2011 S&P downgrade, the US was still a AAA country. But now with the downgrade today, it is no longer the case.

expected fiscal deterioration over the next three years

• the government lacks a medium-term fiscal framework, unlike most peers, and has a complex budgeting process.
• only limited progress in tackling medium-term challenges related to rising social security and Medicare costs due to an aging population.
• Over the next decade, higher interest rates and the rising debt stock will increase the interest service burden, while an aging population and rising healthcare costs will raise spending on the elderly absent fiscal policy reforms.

interest payment/GDP is a more appropriate metric to look at

finances worse in 1992. It's worsened recently but nowhere near 1992.

Fitch's downgrade  is dubious but it should serve as a reminder to the US

a high and growing general government debt burden

The US Treasury boosted the size of its quarterly sale of longer-term debt for the first time in over 2 1/2 years, testing dealers’ appetites amid an increase in government borrowing needs so alarming it helped spur Fitch Ratings to cut the US sovereign rating from AAA.

The Treasury said it will sell $103 billion of longer-term securities at its so-called quarterly refunding auctions next week, which span 3-, 10- and 30-year Treasuries. That’s up from a $96 billion total last time, and slightly larger than most dealers had expected.

Part of that deterioration is thanks to higher interest the Treasury now pays on its debt. The Treasury has also said its tax receipts have been weaker than expected. And in the meantime, the Federal Reserve’s continuing runoff of its holdings of Treasuries, of up to $60 billion a month, requires the government to sell more to the public.

 the erosion of governance relative to 'AA' and 'AAA' rated peers over the last two decades that has manifested in repeated debt limit standoffs and last-minute resolutions.

here has been a steady deterioration in standards of governance over the last 20 years, including on fiscal and debt matters, notwithstanding the June bipartisan agreement to suspend the debt limit until January 2025.

Treasury Secretary Janet Yellen responded to the downgrade, calling it “arbitrary” and “outdated.”

FITCH DIRECTOR SAYS   DEBT CEILING SUSPENSION, OR A VERY HIGH BORROWING  LIMIT, COMBINED WITH DEBT TO GDP STABILIZATION, COULD LEAD TO AN UPGRADE

The bond market shrugged off the downgrade. The yield on 10-year Treasuries was little changed in the London session, while the equivalent rate on German securities fell modestly. Risk-sensitive assets took a hit, with Europe’s Stoxx 600 Index tumbling the most in a month and US futures pointing to losses at the open.

The thing about a nation's credit downgrade is that it generally feeds through models to all banks and corporate borrowers too as a proxy for political risk. This downgrade directly questions the fiscal and governance competence of the USA. It will have a wider impact eventually.

The move by Fitch now gives the US two AA+ ratings. That could raise a problem for funds or index trackers with a AAA-only mandate, opening up the possibility of forced sales for compliance reasons.

The group of countries that still get top marks on their credit worthiness is a declining bunch. Australia, Germany, Singapore, and Switzerland still have the top ratings from all three firms, according to data compiled by Bloomberg. Fitch also rates Canada at AA+. China, the world’s second-biggest economy after the US, has an A+ score from the firm, three notches lower. The sovereign’s rating can act as a ceiling on how high a company in that country is assessed but not in all cases. The number of companies with a AAA level ratings from any of the big three assessors is a dwindling cohort, but it includes household names such as Microsoft Corp. and Johnson & Johnson.