"As a result, the most likely outcome is that in the 75th year, the government will end up with a big pile of debt, requiring large interest payments."

Social Security may run out of full funding by 2032. If Congress does not act, millions of Americans could face benefit cuts of about 22%.

The new date exposes a hard political math: debt above 100% of GDP, 2.4 million fewer immigrants and a tax bill that already trimmed program revenue.

"As a result, the most likely outcome is that in the 75th year, the government will end up with a big pile of debt, requiring large interest payments."