Interest payments on the debt eventually become so burdensome that bondholders demand higher interest payments (Greek debt recently yielded over 30%). Interest rates on US government debt remain low, so this threat is prospective, but future deficits will be far higher than government projections when rates normalize.
高债务、低增长是十分可怕的。债务利息支出将越滚越大直到债权人要求更高的利息（两年期希腊债券当前收益率超过30%）。目前美国国债利率仍然很低，因此这一威胁还比较遥远，但一旦利率正常化以后，未来赤字将会远高于政府的预测值。