The Florida primary leaves Americans with a clear choice — but it isn’t a choice between Republicans and Democrats. Watching the race from across the Atlantic, it seems to me that the real divide is between those candidates who think the main issue is the economy and those who think it is the war.

In the former camp are not only Barack Obama and Hillary Clinton, but also Mitt Romney and Mike Huckabee. In the latter camp, now that the Giuliani campaign is over, only John McCain is left.

The choice is obviously crucial not only for Americans, but also for the rest of the world too. Europeans in particular will be doubly affected by the outcome, not just because America offers leadership, but because their democracies are always influenced by the direction of American politics.

Europe certainly does not see the choice in such clear-cut terms. Despite the terrorist attacks in Madrid and London, there is little sense that the West is engaged in a war of survival — a war that we did not choose, but which was declared against us at the latest on September 11. The operations in which European troops are or have been involved are seen rather differently: as exercises in peacekeeping or nation building. Apart from the Americans, not to mention the Iraqis and Afghans themselves, only the British have been doing much serious fighting, and even they have now effectively left Basra and its surrounding provinces to its own devices.

Only in Afghanistan — where the threat is increasingly coming from across the border in Pakistan — is NATO face to face with the jihadist enemy. It will be interesting to see how strong the European commitment is when the inevitable Taliban spring offensive begins.

Back home, the press is full of fears of impending recession in America, which is predicted to have dire consequences in Europe too. But in reality the anxiety is greater in Europe than in America itself, as the stock market turbulence showed last week.

My fear is that the economic downturn will divert attention from the global jihad, which is waged relentlessly. The jihad is as much a culture war as a terrorist one, and there will be no truce while the West sorts out its financial markets.

Ever since the 1970s we have seen that periods of economic crisis have coincided with an increase in attacks. A reminder of the early days of terrorism was provided by the death this week of George Habash, the founder of the Popular Front for the Liberation of Palestine. It was the PFLP that carried such terrible crimes as the Entebbe hijack, when the passengers were rescued by an intrepid Israeli commando raid, and the Lod airport massacre, in which 27 people were shot at random. The West was slow to react to enemies like Habash and Arafat, not least because the Organization of the Petroleum Exporting Countries oil shock of 1973 left the European and American economies vulnerable.

In the years preceding the attacks of September 11, 2001, the end of the dotcom boom was a huge distraction from the impending threat of jihad — even though Islamists had already launched attacks all over the world.

In this election year, Americans must beware of siren voices repeating: “It’s the economy, stupid.” It is quite easy to talk oneself into a recession, or to make a mild one worse. An even more serious mistake is to elect a leader who tells the nation what it wants to hear — that the war will end when the troops are brought home, even though it did not begin at a time and place of our choosing, and that the economy is a much more pressing concern anyhow.

Many peacetime leaders prove to be war leaders too: look at Lincoln or Roosevelt. But others are hopeless: LBJ was brave on civil rights but unequal to Vietnam. It would be risky to the point of folly for Americans now to elect a leader on the assumption that the qualities required are those of peacetime.

America and Europe are, whether they like it or not, at war with jihadism. As George Weigel argues in his eloquent new book “Faith, Reason, and the War Against Jihadism,” we do not have the safe option of bailing out of this war in order to sort out our economies.

“Victory in the war against global jihadism will require sacrifice; that is obvious,” Mr. Weigel writes. “What is perhaps not so obvious is the nature of the sacrifice required to deserve victory in the war against this particular threat: the sacrifice of our addiction to instant gratification and immediate success.”

When Mitt Romney dismisses John McCain on the ground that he does not know how to run an economy, he is missing the point. Unless the jihadists are decisively defeated — militarily, politically, intellectually — there will be no economy left to run. Let the economy take care of itself. The first and last job of a president is the defense of the nation.