If we choose only to expose ourselves to opinions and viewpoints that are in line with our own, studies suggest that we become more polarized, more set in our ways. That will only reinforce and even deepen the political divides in this country. But if we choose to actively seek out information that challenges our assumptions and our beliefs, perhaps we can begin to understand where the people who disagree with us are coming from…. The practice of listening to opposing views is essential for effective citizenship. It is essential for our democracy.

BARACK OBAMA, remarks at University of Michigan, May 1, 2010

“It is essential to discovering the weaknesses and vulnerabilities of my opponents so that I can destroy them.