# America's $40 trillion problem

> David Rubenstein says interest on the national debt now outruns defense spending, and history says that is a warning sign.
- Title: America's $40 trillion problem · Yahoo Finance | Shortify
- Summary: David Rubenstein says interest on the national debt now outruns defense spending, and history says that is a warning sign. When a country pays more to…
- Keywords: national debt, interest rates, fiscal policy, defense spending, treasurys, business, finance, America's, trillion, problem, Yahoo Finance
- Source: Yahoo Finance — https://finance.yahoo.com/markets/article/ballooning-us-debt-is-a-ticking-time-bomb-billionaire-investor-david-rubenstein-says-130757123.html
- Published: 2026-09-15T13:07:57+00:00
- Read time: 1 min
- Topics: national debt, interest rates, fiscal policy, defense spending, treasurys, business, finance
## The bomb is already ticking
Carlyle Group co-founder David Rubenstein says the $40 trillion US debt pile is a ticking time bomb, and the damage lands first on national security.
## A 400-year warning sign
Rubenstein points to a historical pattern: when a country's interest bill exceeds its defense bill, that country is weakening. The US crossed that line.

> whenever a country paid more interest on its debt than it did for its national security, that's a sign of weakness
## A trillion each, and diverging
Interest runs a little over $1 trillion a year. Defense runs about $1 trillion. As interest climbs, the money left for defense shrinks.

> the interest goes up, and the money available for defense goes down
## A record broken since 1991
Interest now eats 18.5% of federal revenue, topping the 18.4% record set in 1991. The share has more than quadrupled in four years, to $1.25 trillion.
## One in five dollars, gone
Nearly $1 of every $5 the government collects goes straight to servicing old debt, not to infrastructure, Social Security, or defense. Then it borrows more to cover the interest.
## It reaches your wallet
Rubenstein's end state is higher rates across the board: pricier mortgages, pricier borrowing, pricier credit cards. Washington's math shows up in your monthly bill.

> It makes it more expensive for housing, more expensive to borrow money, more expensive for credit cards.
## Key takeaway

When a country pays more to service its debt than to defend itself, the debt stops being a number and starts being a national security problem.