Washington ? One sense of what security means in the age of terror arrived via the self-confident words of a senior French official during a recent chat in Paris: “We know where to find 90 percent of the people who are threats in this country. We can and do track them.”

Later that day, a French woman who is a lawyer told me of having been stopped for an identity check while driving in Paris a week before:

“There were twin messages in the intrusive grilling I got. One was that the police have a free hand today in France. The other was meant to be reassuring. If we are treating you like this in an upscale quarter of Paris, think about what we are doing in the Arab ghettoes that you fear.”

These conversations took place as the French National Assembly was passing a law to forbid Muslim girls wearing headscarves to public schools. The law was framed more broadly than that — it prohibits displays of any religious symbols in state schools — but its true focus was widely understood. At some level, the measure was meant to reassure the French that their government was not afraid of confronting Muslim fundamentalists at home.

This concern is not confined to France. Across the channel, Britain’s Labor government is raising funding for its MI5 internal security force by 50 percent to pay for 1,000 new agents, many of whom will be recruited “from ethnic minorities with the language skills to infiltrate radical Islamic groups in Britain,” according to The Daily Telegraph.

MI5 will grow from 2,100 staffers to 3,000 this year as the budget jumps to about $2.5 billion. Increases for the British equivalents of the CIA and NSA will be limited to matching inflation. There can be no more eloquent statement of the differences in the way Europeans and Americans are fighting the global war on terrorism.

While America is at war abroad, Europe is on alert at home. These differing priorities and responses to 9-11 and its aftermath have led to two years of misunderstandings and controversy across the Atlantic. But both Americans and Europeans need to draw from each other’s approach and resources to reduce their mutual vulnerabilities to religiously inspired fanatics bent on destroying modern society.

As a global military power, the United States relies more on sending soldiers and spies abroad to fight far from American shores. The Pentagon and CIA have identified a global insurgency that they are countering with military and espionage strategies that still reflect the all-or-nothing stakes of the Cold War. George W. Bush proclaims himself a war president.

Europeans depend more on national police forces with sophisticated internal intelligence operations, which Americans are reluctant to accept. It is no accident that the most popular politician in France today is Nicolas Sarkozy, the ambitious interior minister who has made his name synonymous with a pervasive and tough police presence. Similarly, Britain’s David Blunkett and Germany’s Otto Schily, Sarkozy’s counterparts, overshadow most of their Cabinet colleagues at home.

In one sense, both continents follow the hammer-and-nail theory of international politics. Governments, like individuals, often define a problem by the tools that are available to deal with it. But Americans need to understand the extent to which European responses are also driven by the perception that their security problems are internal, rather than located in distant lands.

In the United States, Muslims number 6 million to 7 million, or about 2.4 percent of the population. Americans by and large do not see this minority as a threatening one. It includes some misguided individuals who have gone to Afghanistan, Pakistan or even Europe to join al-Qaida. But Muslim communities in the United States are not seen as the breeding grounds for Islamic extremism — as they are in those European countries where Muslim minorities are more sizable and much less assimilated than in America.

Afraid of being accused of racism, mainstream politicians in Europe have avoided talking about the growing problems of Muslim ghettoes. Even in passing the headscarf law, French lawmakers could not avow their real motives. They depend on the security forces to make their statements on the ground.

Governments on both sides of the Atlantic need to talk more directly and honestly to their own publics about these differences in perceptions as well as the more publicized trans-Atlantic differences in capabilities.

Europeans have a larger role to play in the military campaigns to deny terrorists training camps in Afghanistan, Iraq and elsewhere. And Americans need to show that they can do more about the problem of Islamic fundamentalism abroad than shoot at it.

Jim Hoagland is a columnist for Washington Post Writers Group.