Instant polls taken after Tuesday night's town hall debate suggest that viewers believe President Obama performed better than GOP presidential nominee Mitt Romney -- but not by the overwhelming margins the Republican enjoyed after the first presidential debate. 

A snap CNN/ORC International poll found that 46 percent of respondents thought Obama won, compared with 39 percent for Romney. But nearly half said the debate did not make them more likely to vote for either candidate, and the other half was evenly divided between the two.

In a CBS News/Knowledge networks poll of just undecided voters, 37 percent thought Obama won, 30 percent chose Romney and 33 percent called it a tie. 

Both results are within the polls' margins of error. And the New York Times' Nate Silver notes that historically, instant post-debate polls are not great predictors of actual poll movement.

Polls taken after last week's vice presidential debate suggested a tie between Vice President Biden and Paul Ryan.