By Tony Romeo

HARRISBURG, Pa. (CBS) - A new poll shows Rick Santorum surging among Republican voters in Pennsylvania in the race for the GOP presidential nomination.

The Franklin and Marshall College Poll shows Rick Santorum leading Mitt Romney by a wide margin among Pennsylvania Republicans, 45-percent to 16-percent. But poll director Terry Madonna says equal proportions of Santorum and Romney supporters – 46-percent – say they could still change their minds.

And equal numbers of each candidate’s supporters – 43-percent – say the other guy would be their number two choice. The upshot, Madonna says, is that the race is volatile and the candidates and their commercials haven’t gotten here yet.

“Once the race got joined here, we fully expect that it would tighten, just as we’ve seen it tighten in other states.”

But Madonna believes it is a two-man race. And he says while Santorum has closed the gap with President Obama, he still trails by eight points among all voters. Romney is also eight points back.