Before the first presidential debate, President Obama was the overwhelming favorite. Now the good money is on Rep. Paul Ryan to beat Vice President Biden tonight -- though not by the wide margins Obama was expected to defeat Mitt Romney. 

According to a NYT/CBS/Quinnipiac poll, a plurality of voters in Colorado, Virginia and Wisconsin expect Ryan to win the only vice presidential debate. 

Nearly half of likely voters in Colorado and Wisconsin said they expected Mr. Ryan to beat the vice president, and voters in Virginia gave Mr. Ryan a slight edge over Mr. Biden, 41 percent to 36 percent.

Pew found voters nationally divided on who would do better, with Ryan narrowly edging out Biden 40 percent to 34 percent. Republicans were more confident in Ryan than Democrats were in Biden, and independents bet on Ryan 42 percent to 25 percent.

Meanwhile Republicans are trying to lower expectations. "This is his first time," Republican National Committee Chairman Reince Priebus said of Ryan on CNN Thursday morning. "Joe Biden's been doing this since the 1800s."