Foreign Debt

Niall Ferguson, Hoover senior fellow and Prof of History at Harvard, has a provocative suggestion: the U.S. may suffer the same sort of collapse as the Ottoman Empire because the U.S. is positioned to default on foreign debt like the OE was/did. He cites both the amount and the type of the debt held by foreign entities, describing that because our bonds are denominated by the dollar, the sliding value of the dollar could cause default. Here he is on BBC World Service Business Daily.

Is this a legitimate peril?