Rick Santorum suspended his bid for the presidency on Tuesday, removing the last significant obstacle in Mitt Romney's march to the Republican presidential nomination.

"We made a decision over the weekend that while this presidential race for us is over for me, and we will suspend our campaign effective today, we are not done fighting," Santorum said at a press conference in Gettysburg, Pennsylvania.

Santorum did not endorse Romney in making his announcement Tuesday, though he did vow to fight to defeat President Obama and help Republicans win the Senate in the fall.