Imagine a conservative leader who slashed spending across the board, ranging from social outlays to the military. It would raise howls of indignation on both the American left and right. But that's what Prime Minister David Cameron is doing in England--proposing a sweeping austerity program designed to put the island nation back on a firm financial footing.

Given that American neoconservatives have been calling for Europe to up its defense outlays, Cameron's action is coming as something of a shock in America. Max Boot complains, in the Wall Street Journal, that "the days of British military power appear to be ending--with the obituary written, ironically, by a Tory-dominated government supposedly dedicated to a strong defense." Actually, British observers themselves are taking a somewhat different view. In Foreign Policy, Alistair Burnett observes,

Nuclear weapons or not, it seems clear Britain intends to remain a useful ally to the United States and its NATO partners, with a renewed attempt to work more closely with the French.

What remains open to question is how that power will be used in the future. Cameron also signaled that Britain would be less interested in large-scale military interventions along Iraqi or Afghan lines, and instead would focus more on using diplomacy and aid to prevent conflicts from breaking out in the first place. It's just as well: That might be all a cash-strapped Britain may be capable of doing anymore.

The problem with the Boot analysis is simple: while it might be desirable, in theory, for America to continue massive outlays for defense, can it afford to do so any more than its British cousins? Or is the United States, in fact, a declining power that faces a permanent and irreversible erosion of its economic might that will dictate cuts in defense spending along the lines of the British?

What Americans themselves have not yet comprehended, or accepted, is that their standard of living is going to fall over the next decade. The era of prosperity is over. At a moment when unemployment is nearing 10 percent and the budget deficit is soaring, it seems unlikely that a defense budget that is projected to be around $800 billion is sustainable. President Obama's deficit commission, which will issue its recommendations in January, is likely to push for cuts in both social and military spending as well as targeted tax hikes.

In England Cameron didn't need a deficit commission. He acted boldly and courageously. Instead of complaining about his defense cuts, conservatives should be looking to emulate them and reexamine America's commitments abroad. If the GOP had a politician like Cameron, it would be a shoo-in to win the 2012 presidential election.