Both the Obama campaign and the Romney campaign have been working to lower expectations for their respective sides. The official who confirmed the debate session last week continued to lower expectations for Biden saying that Ryan, the chairman of the House Budget Committee, has a "notable grasp" of budget-related topics.
"The Vice President has been preparing for his debate with Congressman Ryan – a candidate who has an exceptional grasp of policy details and budgetary matters," the official said. "He and Congressman Van Hollen have held their first mock debate session."
The Obama campaign appears to be anticipating the vice presidential debate to have a heavy emphasis on budget related topics. Van Hollen is the ranking Democrat on the House Budget Committee, a panel that Ryan is the chairman of.