STEUBENVILLE, Ohio (AP) - Philosophical differences between the top two Republican presidential candidates are becoming starker.

Rick Santorum is driving harder on religious and social issues while Mitt Romney rarely discusses them in detail.

Santorum in recent days has questioned the usefulness of public schools and said President Barack Obama's theology is not "based on the Bible."

Campaigning in Ohio on Monday, he likened Obama to politicians who spread fear about certain technologies "so they can control your lives."

The remarks contrast sharply with Romney's steady 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 image and identity heading into the fall battle against Obama.