Sven at Defense and Freedom cites some interesting statistics about debt as a percentage of GDP in Europe and Japan. It's certainly bigger in many cases than I expected. However, I'm not 100% sure of the conclusion:
This government debt situation has
certainly implications for the ability to spend the same or more on
military power in the future. The Grand strategy of NATO and its
nations should attempt to avoid large arms races due to its mature and
not vital enough economies/societies/governments.
The next several years will be the real test of how much debt constrains military power--at least for the United States. Assuming a more parsimonious regime than the debt-happy Bush Administration and Congress of 2001 to 2007, how fast can the US government return to a point where it can afford to fight another regional war? And even if it can't afford it, will the United States fight future wars anyway? Would it be restricted to the Operation DESERT SHIELD/STORM model, in which other countries that benefit from US military action help pay the bill?
In the last few weeks, we may have just seen the biggest constraint on future American military action: the interconnectedness of national economies. We were already likely to see a revival of multilateralism in US foreign policy, after the Bush Administration's failed experiment in weak coalitions and unilateralism. Now, we know that, if expensive military venures weaken the US economy, the cascade effect will hurt other economies as well. Even if a future President didn't want to embrace multilateralism, other countries might not leave us much of a choice.