AP

STEUBENVILLE THE 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 eventempered 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 November election against Obama. They also will test whether social conservatives and supporters of the small government, anti-tax tea party movement can outperform the Republican establishment in key states such as Michigan and Ohio.

The Republican party establishment is believed to be deeply concerned about Santorum eclipsing Romney, the former Massachusetts governor and multimillionaire venture capitalist.

Romney still holds an edge in delegates to the party’s nominating convention this summer and a huge financial and organizational advantage. But conservatives have shown a deep discontent with his candidacy over his past, more moderate views on sensitive issues such as abortion.

It’s not unusual for the Republicans to face intraparty struggles between conservatives focused largely on social issues such as abortion and school prayer, and those focused mainly on financial matters such as spending and taxes. Sometimes the quarrels become loud and problematic, as when conservative commentator Pat Buchanan called for a “culture war” at the 1992 Republican national convention. President George H W Bush, already facing troubles, lost to Bill Clinton that fall.

Santorum, a staunch opponent of abortion and gay rights, surged past Romney in recent opinion polls of Republican voters after winning contests in Minnesota, Colorado and Missouri on February 7. Several polls have shown Santorum leading in Romney’s native state of Michigan, where his father served as governor.

The primaries in Michigan and Arizona on February 28 mark the end of a lull in the state-by-state contests.