<p>He said so himself in March, when he vowed to continue pressing for changes to Social Security despite the qualms of Congress and the public. "I'm going to be stubborn on this issue," he said in Iowa.</p>
<p>He demonstrated his persistence again Wednesday, when he gave another speech promoting changes he wants to make in Social Security. "My strategy is pretty simple: Explain the problem to the American people, and keep explaining it and explaining it," he told the Association of Builders and Contractors.</p>