GREEN BAY, Wis. — Rick Santorum is vowing to press forward with his presidential bid after a victory in Louisiana.

The former Pennsylvania senator on Saturday said he is "still here" and "still fighting," even as front-runner Mitt Romney was far ahead in the critical race for delegates.

In a victory speech, Santorum insisted his conservative principles are "sketched on our hearts," a jab at the former Massachusetts governor. A top Romney aide this week compared the move from a primary into a general election to an Etch A Sketch toy, implying they could be erased and redrawn.

Santorum soundly beat Romney in Louisiana Saturday, adding another Southern win on top of victories in Tennessee, Alabama and Mississippi.

But he was campaigning in Wisconsin, the next critical battleground. Wisconsin votes April 3.

Also on HuffPost: