It may not appear to be costly at present, since risk-averse individuals conscious of credit risks, and foreign countries running massive trade surpluses, are still willing to accumulate the Treasury securities being issued, with no apparent impact. But ultimately, those securities will either stand as claims on our future national production, or they will be inflated away. Either the Treasury securities will retain value, so that holders such as China get to use them to acquire our productive assets in the future, while we ultimately tax ourselves in order to pay off that debt, or we must dilute the ability of those Treasuries to claim real goods and services, which is another way of saying we inflate away the debt.There are two mistakes here, a tiny one and a more important one. First, it is wrong to say that foreigners will in the future acquire more U.S. productive assets: they already, today, by buying these newly issued securities, receive a higher share of U.S. national income through interest. Interest comes from taxes, which are paid thanks to productive assets. In other words, whether foreigners swap their Treasuries for U.S. equities or stick with their Treasuries, they still claim larger share of U.S. assets.
The second, bigger mistake is to believe that the U.S. can choose to swap an international redistribution of wealth problem (the 'either' part of Hussman's argument) for a national redistribution of wealth through inflation. There is no free lunch. 'Inflating away' the national debt is not a good expression as the debt doesn't really go 'away': it is just swapped for other securities, while the same amount is owed to foreigners.
To be specific, inflation will not resolve anything because it will result in a deterioration in the trade balance (higher pricing power to foreign producers), which itself will result in a deterioration in next external assets (claims on foreign assets minus domestic assets owned by foreigners). When all is said and done, the U.S. NIIP (Net international investment position) would have been the same with or without inflating the debt
Inflation does redistribute wealth from savers to borrowers inside a country. It does not allow a nation to escape from transferring its wealth abroad. There is only one way to do that: default.