PRAGUE  In the 1980s, a Communist secret police agent infiltrated clandestine economics seminars hosted by Vaclav Klaus, a fiery future leader of the Czech Republic, who had come under suspicion for extolling free market virtues. Rather than reporting on Marxist heresy, the agent was most struck by Mr. Klaus’s now famous arrogance.

“His behavior and attitudes reveal that he feels like a rejected genius,” the agent noted in his report, which has since been made public. “He shows that whoever does not agree with his views is stupid and incompetent.”

Decades later, Mr. Klaus, the 67-year-old president of the Czech Republic  an iconoclast with a perfectly clipped mustache  continues to provoke strong reactions. He has blamed what he calls the misguided fight against global warming for contributing to the international financial crisis, branded Al Gore an “apostle of arrogance” for his role in that fight, and accused the European Union of acting like a Communist state.

Now the Czech Republic is about to assume the rotating presidency of the European Union and there is palpable fear that Mr. Klaus will embarrass the world’s biggest trading bloc and complicate its efforts to address the economic crisis and expand its powers. His role in the Czech Republic is largely ceremonial, but he remains a powerful force here, has devotees throughout Europe and delights in basking in the spotlight.