STEUBENVILLE, Ohio — Philosophical differences between the top two Republican presidential candidates are becoming starker as Rick Santorum drives harder on religious and social issues that Mitt Romney rarely discusses in detail.
In recent days, Santorum has questioned the usefulness of public schools, criticized prenatal testing and said President Barack Obama's theology is not "based on the Bible." On Monday, he likened Obama to politicians who spread fear about new oil-extraction technologies "so they can control your lives."
The remarks contrast sharply with Romney's even-tempered emphasis on jobs, the economy and his resume as a can-do corporate executive.
The differences give Republican voters clear choices to shape their party's identity and image heading into the fall battle against Obama. They also will test whether social conservatives and tea partyers can outperform the GOP establishment in key states such as Michigan and Ohio.
Both men campaigned Monday in Ohio, where their audiences, styles and messages produced distinctly contrasting atmospheres.
Santorum, the former senator from Pennsylvania, appeared in Steubenville before a packed room including many students and employees of the town's Franciscan University. In his hour-long talk, Santorum never mentioned Romney or Newt Gingrich, who campaigned in Oklahoma.
He aimed squarely at Obama as he discussed abortion, marriage, the church and family. When he touched on non-social issues such as energy and the environment, he couched them in terms of epic struggles between reasonable conservatives and radical, sometimes devious Democrats.
"I refer to global warming as not climate science but political science," Santorum said to loud applause. He said Obama has "radical environmentalist policies" that reject robust extraction of oil and gas from many U.S. areas, including the Arctic National Wildlife Refuge in Alaska.
In Cincinnati, on the opposite side of the state, Romney hit Santorum's spending record as a member of Congress but stayed away from the former senator's recent comments on social and other hot-button issues.