Virtually everyone who follows these issues knows that the U.S. national debt is over $17 trillion. The U.S. Treasury issues daily statements on the national debt here. The latest report is that for March 25, 2014 (.pdf). It lists the closing balance for “Total Public Debt Outstanding” at $17,555,984,000,000, which is over $17.5 trillion dollars.
Of that amount, $4,976,757,000,000 (almost $5 trillion) consists of “intragovernmental holdings,” and $12,579,227,000,000 (over $12.5 trillion) is “debt held by the public.” That latter number is what Yglesias is citing, as you can tell from the chart that accompanies his narration, which has a bar on a chart labeled: “Debt held by the public.”
But the debt held by the public is not the U.S. national debt. And Yglesias didn’t say the debt held by the public is $12.5 trillion. Matt Yglesias said that “The United States’s national debt” is $12.5 trillion. That is false, and I believe Yglesias knows it’s false.