Republican vice presidential candidate Paul Ryan (Wis.) sought to lower expectations for the first presidential debate, saying Sunday he doesn't believe a single event will dramatically alter the shape of the campaign. 

"I don’t think one event is going to make or break this campaign," Ryan said on "Fox News Sunday. 

Ryan said the country can expect his running mate, Mitt Romney, to set up a stark choice on Wednesday, when he and President Obama debate in Denver, for the first time. 

“I think what people are going to see is, who is Mitt Romney. What kind of president is he going to be and what are the choices I have. That, to me, is what matters in this particular debate, and all the debates," Ryan said. 

Host Chris Wallace asked whether the choice argument represented a shift away from the effort to turn the race into a referendum on Obama's policies.

"It's not change in the strategy. It's a phase of the campaign we've now entered," Ryan responded.

Looking ahead to the Oct. 11 vice presidential debate, Ryan said that Vice President Biden is very good at confusing viewers about the issues that matter.

"Joe is very good on the attack. Joe is very good at trying to confuse the issues," Ryan said, adding: "My job is to make sure they are not confused." Ryan said he is not counting on Biden making a gaffe. 

Ryan also weighed in on foreign policy, bashing the Obama administration's handling of the attack at an American consulate in Benghazi, Libya, that claimed the life of four Americans including Ambassador J. Christopher Stevens. Obama administration officials first said the attack was spontaneous, but later concluded it was an act of terror with ties to al-Qaeda. 

"The response was slow. It was confused. It was inconsistent," Ryan said. 

Ryan also talked about the GOP ticket's proposed 20 percent cut in tax rates for all Americans. But he said a lengthy discussion would be required to go through the specifics of it. "It would take me too long to go through all the math," Ryan said.