Even before the British Defense Ministry this week elected to scrap the Royal Navy's only fixed-wing-aircraft carrier, nobody imagined that Britannia still ruled the waves - or had any of the power that characterized its empire before the two world wars of the past century.

Still, as recently as a decade ago, Britain could take solace in its "special relationship" with the sole surviving superpower, earning pride of place among U.S. allies with its readiness to commit substantial numbers of troops to Washington's expeditionary military ventures. Sure, the 46,000 troops the British sent to Iraq for the U.S.-led invasion equaled around one-third of the American force, but the U.S. military was almost 10 times larger than Britain's. In Afghanistan, also, the U.K. committed a force equivalent to one-third of the U.S. deployment. In both cases, Britain's contribution dwarfed that of other NATO allies.

But the defense spending cuts announced this week as part of the British government's massive deficit-cutting austerity program mean that the next time America goes to war in some distant land, it is unlikely to be joined by significant numbers of British squaddies. Besides scrapping (for at least a decade) its naval capacity to send air power overseas, the U.K. will cut its defense budget by 8%, losing 17,000 personnel and cutting back its armory of tanks and artillery.

The maximum number of troops that the reconfigured British military will be able to deploy in any new sustained expeditionary operation will be 6,500. While its leaders gamely insist that Britain will continue to "punch above its weight" as a military power, the message for the U.S. in Britain's contraction may be a lot more sobering than simply the retrenchment of military capability by its most trusted ally. Britain's case may have illustrated the iron law that fiscal deficits inevitably corrode a nation's ability to project power beyond its shores.

Britain's Defense Cuts: Grim Portent for US Military?