The endorsements are part of a larger plan by Santorum to focus on conservative causes.

Santorum, according to Davis, will focus his efforts on a number of battleground states: Colorado, Iowa, Michigan, Missouri, North Carolina, Ohio, Pennsylvania, and Virginia.

Besides campaigning, Santorum is promoting his book: “American Patriots: Answering the Call to Freedom.” The tome comes out Tuesday and Santorum will appear on “The Late Show with David Letterman” the following day.

Brad Todd, a Republican strategist, said Santorum seems to be following the playbook of Rep. Jack Kemp (R-N.Y.) before he ran for president.