The latest Quinnipiac poll, which shows Mitt Romney just four points behind Barack Obama in Pennsylvania, also shows a three-point Senate race. The incumbent, Democrat Bob Casey, Jr., leads his Republican challenger, Tom Smith, 48 percent to 45 percent, with 7 percent undecided.

Smith, a relative newcomer to politics running in his first state- or federal-level election, cut Casey's lead in half from Quinnipiac's last poll of the race a month ago. While some recent polls have shown Casey maintaining a better lead, only 1 poll in the last 6 weeks has shown the first-term Democratic senator breaking the 50 percent threshold. To top it off, it appears that Casey is running behind President Obama in Pennsylvania, while Smith is running ahead of Romney. That suggests some voters may be considering splitting their ballot between Obama and Smith.

On the other hand, a recent poll from PPP, a Democratic firm, shows Casey with an 11-point advantage. The Real Clear Politics poll average shows Casey's lead down to 5.3 points.

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