Rivals Vow to Fight on Despite Romney's Nudge His delegate lead growing, Mitt Romney gently nudged his Republican opponents toward the sidelines on Wednesday and said he was on track to wrap up the presidential nomination before the party convention next summer. Rick Santorum and Newt Gingrich paid him no mind, vowing to fight on in a campaign marked by persistent ideological divisions. If anything, the political maneuvering intensified as the marathon pointed toward contests in five states over the next week. Romney's campaign purchased television advertising time in Alabama according to campaign sources, as it pursued a breakthrough in the party's Southern base. A Santorum ally urged Gingrich to abandon the race. In response, the former House speaker said he would consider it - if he thought Santorum was sure to beat Romney and then President Barack Obama. "I don't," he added. And when Santorum was informed that an aide to Romney had said it would take an act of God for any other candidate to amass a majority of convention delegates, Santorum responded heatedly. "What won't they resort to to try to bully their way through this race?" he said in Lenexa, Kan. If the governor now thinks he's now ordained by God to win, then let's just have it out. One day after Super Tuesday, Romney's campaign circulated a memo making the case that his six victories on a single night had increased his delegate lead to a point that it was increasingly hard for any of his rivals to catch up. And they were hurting the party by continuing to try, it suggested. "As Governor Romney's opponents attempt to ignore the basic principles of math, the only person's odds of winning they are increasing are President Barack Obama's," it said. Romney didn't go that far in an interview, and he stopped short of a flat prediction that he would achieve his goal of a pre-convention delegate majority. "We think that will get done before the convention, but one thing I can tell you for sure is there's not going to be some brokered convention where some new person comes in and becomes the nominee," he said on CNBC's "Squawk Box." It's going to be one of the four people that are still running. After Super Tuesday, Romney has 419 delegates overall, more than his three rivals combined. Santorum is second with 178, Gingrich has 107 and Paul has 47. It takes 1,144 to win the nomination. While Romney clearly would like all his opponents to drop out, the departure of just one - either Santorum or Gingrich - might be less welcome. The two often divide the anti-Romney vote and enable him to win contests he might otherwise lose. In Ohio, the marquee matchup on Tuesday, Romney edged Santorum by a little more than 10,000 votes out of 1.2 million cast. Gingrich drew about 175,000 votes and Ron Paul 111,000. Gingrich and Santorum both argue that despite Romney's financial and organization advantages, he is a latecomer to conservative causes, plagued by inconsistencies in his record and unable to articulate significant differences with Obama.