I wish I could be happier about the outcome of the British elections. There is a naturally tendency, after all, for American conservatives to cheer for British Conservatives. Winston Churchill and Margaret Thatcher are, if anything, more popular in the U.S. than in the United Kingdom. But David Cameron is no Churchill or Thatcher.

To his credit, he has implemented an impressive austerity program, cutting the budget deficit and the public workforce in ways that Republicans can usefully emulate. Certainly he was preferable to Ed Miliband, the most left-wing leader of Labor since Michael Foote in the early 1980s; if Miliband had won, he would by all accounts have implemented socialist policy at home and isolationist policy abroad. (Ed’s brother, David, who lost the leadership election, is much more mainstream in the Blair mold.)

Cameron is vastly better on domestic policy than Miliband but he is not that different on foreign policy. Far from pursuing a Churchillian or Thacherite foreign policy, he is a Randian—as in Rand Paul, not the Rand Corp. or Ayn Rand. Or, as he would have been known in the 19th century, he is a “Little Englander”—Britain’s version of isolationists.

Cameron has shown scant interest in taking an active, interventionist stance as Tony Blair did. He tried and failed to win support in the House of Commons in 2013 for bombing Syria in response to its violations of President Obama’s “red line” on Syria. His defeat not only caused Obama himself to lose his nerve but also led Cameron to scurry off with his tail between his legs. Ever since he has been content to take a backseat in international affairs, letting Germany and France take the lead in negotiations with Russia over Ukraine, for example. When it comes to battling ISIS, Britain’s contribution is tiny and mainly symbolic.

Cameron’s most disastrous policy decisions have been to cut defense spending in ways that make it impossible for Britain to project substantial military force abroad.  My boss James Lindsay, director of studies at the Council on Foreign Relations, has the depressing rundown:

•  In 1990, Britain spent 3.8 percent of its GDP on defense. Today, it spends less than 2 percent. In absolute terms, defense spending has fallen 14 percent since 2010 after accounting for inflation.

• British troop levels have shrunk 19 percent since 2007, and they’re set to shrink another 8 percent by 2020. Even steeper cuts could be on the way. If they materialize, the British army would be the smallest it has been since it lost to the Minutemen at Lexington and Concord.

• In 1996, the British Navy had thirty-six warships—destroyers and frigates. Today, it has eighteen. Britain is building two new aircraft carriers. The first is scheduled to be completed in 2017, three years before Her Majesty’s Navy acquires the planes that will fly off its decks.

Not all of these cuts have occurred under Cameron but he has accelerated these trends since taking office in 2010. On his watch British defense capabilities have fallen so far, so fast that the “special relationship” with the U.S. has become but a memory; even if Britain wanted to play an active role in helping the U.S. to police the world, it would be unable to do so.

Let’s hope, as Dan Twining suggests, that Cameron will use his second-term, now that he no longer has to share power with the Liberal Democrats, to pursue a more muscular national security policy. Certainly his isolationism is not demanded by the public; in a recent survey 63 percent of Britons said they wanted their country to continue to be a great power.

Given all the threats that the West faces—from Ukraine to Iran—the United States cannot afford to go it alone and there is on other ally we can count on as much as we have counted on Britain during the past 60-plus years. But unless Cameron radically reverses his first-term trends, the UK will continue to slide into international irrelevance.