A good article by an author I usually don't follow all that much, Paul Kennedy.  Anyway, the key point he makes is that the US (in a manner somewhat akin to ancient Rome and 19th Century England) is the purveyor of international public goods by its enormous military expenditures.  He questions whether the general post World War II consensus that allowed America to devlop this system may be breaking down and posits that if America is ceding this leadership (for example by allowing its banks to be given liquidity by Sovereign Wealth Funds) it could be a major global problem.  I wholeheartedly concur and this is why outside WMD proliferation and the immediacy of a catastrophic attack, it is our long-term domestic spending habits that are going to have to be reformed in order to regain our footing. 

I often return to this theme because it is the issue that will underlay every other issue: education, health care, economic competitiveness, etc.  We have to avoid catastrophic attacks on our nation (or our infrastructure) and we must be able to stem the red ink on our national balance sheet or we will be conceding our position in the world.  Again, the consequences of conceding our place in the world will not be rosy and allow us to "focus on ourselves", it will eventually lead to a chaotic situation globally as new powers seek their moment in the sun (see the below piece on Asia Rising).  Our system keeps everything in some assemblance of balance, without us, so goes the balance.  Our economy will not be benefited from having someone take over relative control of the Middle East and able to dictate oil prices (despite OPEC's problems, they at least have a rational incentive to keep us buying, certain regimes may not).  Our economy will not be benefited if our Navy retrenches and key sea lanes are either run by another power (China, perhaps?) or simply left at the mercy of piracy if no other nation is capable enough of providing the protection we offer.  These are the real issues that sober policy makers must attend to away from the glaring light of the Presidential media parade and sound bite era.