With three weeks before the primary, 6 percent of likely voters remain undecided and 37 percent of those who name a candidate say they still could change their mind, the independent Quinnipiac (KWIN-uh-pe-ack) University poll finds. This is the first look at likely voters and cannot be compared with earlier surveys of registered voters.

Santorum tops Romney 43 – 33 percent among men, while women split 39 – 38 percent. Santorum also leads 53 – 24 percent among white evangelical Christians, 50 – 32 percent among Tea Party members and 48 – 30 percent among self-described conservatives. Romney is ahead 45 – 29 percent among self-described moderates.

“The Keystone State is critical for Sen. Rick Santorum, the native son who must win to reasonably continue the race for the presidency,” said Tim Malloy, assistant director of the Quinnipiac University Polling Institute. “Can Santorum hold on against Gov. Mitt Romney’s money machine which has turned the tide in other states, washing away Santorum’s early leads?