President Bush has vigorously defended his Iraq policies and called for nations around the world to promote democracy. During the keynote address of his state visit to Great Britain, Mr. Bush took on the opponents of the Iraq war.
Mr. Bush says sometimes it is necessary to resort to force in order to protect peace and security.
"In some cases the measured use of force is all that protects us from a chaotic world ruled by force," President Bush explained.
In a speech at London's Whitehall Banqueting House broadcast on British television, Mr. Bush talked about the reasons why he chose military might to oust Iraqi leader Saddam Hussein.
He said it was a last resort, after diplomacy and all other means had failed. And he reaffirmed in the strongest terms that despite recent violence that has claimed the lives of coalition forces and Iraqi civilians, the United States will not turn away.
"We did not charge hundreds of miles into the heart of Iraq and pay a bitter cost in casualties and liberate 25 million people only to retreat before a band of thugs and assassins," he said.
Mr. Bush spoke of the justifiable use of force as a last resort as one of three pillars of security and peace. He said the other pillars are the spread of democracy and the ability of nations to work together to solve common problems.
He said he believes in the value of international institutions, such as the United Nations. But he said the credibility of the U.N. depends on its ability and willingness to keep its word.
"America and Great Britain have done and will do all in their power to prevent the United Nations from solemnly choosing its own irrelevance and inviting the fate of the League of Nations," Mr. Bush said.
The president opened and closed his speech by reflecting on the relationship between the United States and the United Kingdom. There was praise for British Prime Minister Tony Blair who has come under criticism at home for his support of the Iraq war, and a reminder of the historic ties that bind the two nations across the Atlantic.
"More than an alliance of security and commerce the British and American peoples have an alliance of values. And today, that old and tested alliance is very strong," he said.
Mr. Bush acknowledged that there are those in Britain and across Europe who disagree with his views. He said nations, which lived through world wars, and viewed in recent times the brutality of leaders like former Yugoslav President Slobodan Milosevic should understand the need to confront tyranny.
But President Bush stressed even the most vocal opponents of U.S. policy in Iraq have the right to speak out.
"I have been here only a short time. But I have noticed the tradition of free speech exercised with enthusiasm is alive and well here in London," the president said. "We have that at home too. They now have that right in Baghdad as well."
As he talked, anti-war demonstrators were gathering in the streets of London. The largest protest, which organizers say may attract as many as 100,000 people, is planned for the president's meeting with British Prime Minister Tony Blair.