"When you take a look at the problems our country is facing, debt is No. 1. The math is downright scary and the credit markets aren't going to keep on giving us cheap rates"

This quote by Paul Ryan is referring to the current state of the United States economy and the amount of financial obligation the country is dealing with. He is stressing the intensity of the situation, noting that the mathematics is "downright frightening" and that the credit markets are not going to continue to provide cheap rates. This is a caution that the US requires to do something about it to deal with the financial obligation issue, as it is the primary issue the country is dealing with. He is suggesting that the United States needs to take actions to lower the financial obligation, such as cutting costs and increasing revenue, in order to prevent a financial crisis. This quote is a suggestion that the US requires to act now in order to avoid a financial catastrophe in the future.