file-in-this-may-31-2011-file-photo-former-pennsylvania-sen-rick-santorum-left-shakes-hands-with-new-hampshire-state-rep-thomas-howard-before-touring-rugar-firearms-in-newport-nh-santorum-is-set-to-formally-announce-on-monday-june-6-2011-he-is-seeking-the-republican-partys-presidential-nomination