Mitt Romney apparently pulled off a narrow victory over Rick Santorum in Ohio on Super Tuesday. But Mr. Santorum scored victories elsewhere, competing with Mr. Romney’s achievement of collecting the most delegates and all but ensuring another round of intense infighting on the road to the Republican presidential nomination. Far from bringing new clarity to the race as some in the party had hoped, Tuesday’s results gave every candidate cause to keep driving forward —including Newt Gingrich, who won a definitive victory in Georgia. They also dashed Mr. Romney’s hope of using the night to assert himself as the inevitable nominee.