Sometimes it pays to be careful what you wish for. John McCain's challenge to Barack Obama to visit Iraq and Afghanistan created the premise for Obama's trip to the Middle East and Europe this week. That trip may become a major watershed event in the presidential contest. It may also one day be viewed as a significant event in the broader history of our country's relationship with the rest of the world. How can a foreign trip affect Obama's domestic presidential campaign? Of course it doesn't hurt that on the first day of Obama's journey, Iraqi Prime Minister Maliki edged very close to endorsing his plan for American troops to withdraw from Iraq. In an interview in Der Spiegel he is quoted as saying: "U.S. presidential candidate Barack Obama talks about 16 months. That, we think, would be the right timeframe for a withdrawal, with the possibility of slight changes". The trip will highlight the fact that it isn't just the American people who want us to leave Iraq -- all of the polls of the Iraqi people want us out as well -- and now so does the U.S.-backed Prime Minister of Iraq. That leaves Bush, McCain and the neo cons as the only people around still committed to their reckless program of keeping U.S. troops in Iraq far into the future. It puts in full relief McCain's flawed judgment when it comes to foreign policy. Of course, by making his first stop the front lines in Afghanistan, Obama also emphasized once again how Bush, McCain and the neo cons have taken their eye off the ball by diverting resources to an "elective" war in Iraq and away from the central front where terrorist cells intent on attacking the United States are actually organized. But there's more. Swing voters are eager to vote for change, but one of the questions holding them back is whether Barack Obama can lead America in a dangerous world. More than anything else, this week's trip will allow them to imagine Barack Obama as Commander in Chief -- to get a sense of how he looks on the world stage. Obama's "world stage presence" should do more than simply reassure them. It will provide a demonstration of how fundamentally Obama will improve the way people around the globe -- and especially young people -- view the United States. Obama's calm, friendly, but decisive style is perfectly suited to the world of international politics. If he is elected, his own story and background will instantly engage the imagination of young people -- especially the 80% of young people who live in India, China and the developing world. The very fact that our country would elect a person of color -- someone like them -- to lead us will say more to them about the soul of our people than thousands of pronouncements of policy or millions of dollars spent on "public diplomacy." Obama's ability to inspire will do more than anything else to turn him -- and America -- once again into a beacon of hope and possibility for the billions of people who desperately hope for a better life. People's fundamental life-long views are shaped when they are young. The mental frames they use to place the political world around them into context -- to understand the meaning of what they see and hear -- are largely formed when they are in their late teens and early twenties. Nothing is more critical to our own national security than assuring that future generations of leaders around the world think of America as a progressive force that will benefit their lives rather than an "evil empire" intent on dominating them and preventing them from achieving their own aspirations. Like it or not, it is this latter message that George W. Bush has sent to young people world-wide. The Bush years have convinced vast numbers of young people around the globe that America is the country of neo con unilateralism and preemptive war. It will be very difficult for us to change those perceptions as the current generation of young people ages and takes on responsibilities for running their countries. When it comes to public perception we will pay the price for George W. Bush for years to come. Those perceptions will damage our security for many years. We can't afford to lose another generation. Obama's election -- especially if it is decisive -- would go some distance to shock even those in the "Bush generation" into re-evaluating the way they view America. In the United States, presidents are more than decision-makers and leaders. They are Chiefs of State, symbolic embodiments of the values that define our country. This week Americans -- and people around the globe -- will get a glimpse of what it would be like if Barack Obama becomes the personal embodiment of America in the 21st Century. I believe they will like what they see.