Europe and the United States may always differ in their views of the biggest global security threats and how to respond to them, CIA director Michael Hayden said Wednesday.
In a speech at Kansas State University, Hayden said this "key strategic relationship" had changed, noting that disagreements over Iraq and terrorism "have raised questions in recent years about the future of the alliance."
"I am confident that we will continue to work together on many tough global challenges, as we are today in bringing stability to Afghanistan and in efforts to deter Iran from developing nuclear weapons, for example," he said.
"But it is not yet clear when, or if, the United States and Europe will come to share the same views of 21st century threats as we did for the last half of the 20th century, and then forge a common approach to security."
Hayden was referring to the close relationship between Europe and the United States during the Cold War -- but since the fall of the Berlin Wall "differences are cropping up over a host of issues."
The European-US relationship was no longer primarily focused on Europe, which was now "nearly whole, free, and at peace," so attention was shifting to more global threats, Hayden said.
Wider cooperation had brought great benefits -- it had "thwarted terrorist plots and saved lives" both sides of the Atlantic, he said -- but also more scope for disagreements.
Many of these disagreements centered on the perception of threats and how to deal with them, he said, noting for example that "while we share the view that terrorism is an urgent danger, we disagree on how best to confront it."
"The United States believes it is a nation at war -- a war that is global in scope and requires, as a precondition for winning, that we take the fight to the enemy, wherever he may be," the CIA chief said.
"In much of Europe, terrorism is seen differently: primarily as an internal, law enforcement problem, and solutions are focused more narrowly on securing the homeland."
He said European governments worked with each other and their allies, such as the United States, to confront direct threats, but did not in general share Washington's view that terrorism was "an overwhelming international challenge."
Hayden said managing such tensions would "complicate" the once relatively easy relationship and the effects of the disagreements would be felt "from intelligence and law enforcement to military cooperation and foreign policy."