In the first of a series of three speeches on foreign policy, Blair told an audience of journalists in London that the struggle against terrorism was not a clash of civilizations but "a clash about civilization."
"This terrorism, in my view, will not be defeated until its ideas, the poison that warps the minds of its adherents, is met head-on," Blair said.
Blair conceded that the U.S.-led invasion of Iraq has encountered problems, but maintained that the idea that the invasion was an example of Western imperialism was a "gross overexaggeration" and "nonsense."
Opponents have criticized Blair's willingness to back military intervention in Sierra Leone, Kosovo, Afghanistan and especially Iraq. But Blair said he rejected "the doctrine of benign inactivity" in favor of "a politics of globalization" that sees the world's problems as interconnected.
Blair said the advance of democracy in Afghanistan and Iraq "is the most effective message against (terrorists') wretched propaganda about America, the West and the rest of the world."
He said terrorism would be defeated by a battle of "values and ideas set in opposition to those of the terrorists."
"This is not a clash between civilizations, it is a clash about civilization," he said.
"'We' is not the West, 'We' are as much Muslim as Christian or Jew or Hindu. 'We' are those who believe in religious tolerance, openness to others, to democracy, liberty and human rights administered by secular courts."
But Blair warned that extremism is deep-rooted and its impact felt worldwide, with some 40 to 50 countries subjected to regular terrorist attacks.