The United States faces projected 10-year federal budget deficits that seriously threaten its bond market, exchange rate, economy, and the economic future of every American worker and family. Those risks are exacerbated by the context of those deficits: a low household-savings rate, even after recent increases; large funding requirements for federal debt maturities every year; heavy overweighting of dollar-denominated assets in foreign portfolios; worsened fiscal prospects in the decades after the current 10-year budget period; and competing claims for capital to fund deficits in other countries.
The conventional concern here is that private investment will be crowded out, which would result in a reduction of productivity, competitiveness, and growth. In addition, the very early 1990s showed that unsound fiscal conditions can have a symbolic effect that broadly undermines business and consumer confidence. But finally, and far more dangerously, our bond and currency markets could react with severe distress to fears about imbalances in the supply and demand for capital in the years ahead or about the possibilities of inflation. Those effects have been averted so far by a number of factors: large inflows of capital from abroad into Treasury securities; concerns about other major currencies; the low level of private demand for capital; and the psychological state of the market. But this cannot continue indefinitely, and change can occur with great force—and unpredictable timing.
http://www.economicpolicyjournal.com/2010/01/robert-rubin-all-hell-could-break-loose.html
