When he wasn't off winning Congressional Medals of Honor at the War of 1812, or giving George Washington a lift at Valley Forge, Illinois Republican Mark Kirk was busy violating Pentagon rules about mixing politics with active duty service.

The Pentagon said Republican Senate candidate Mark Kirk has been cautioned twice for improperly mingling politics with his military service, but Kirk's campaign denied any improper conduct Tuesday.

The Defense Department said Monday night that Kirk, a commander in the Navy Reserve, was warned after two incidents of political activity while he was on active duty. Before being allowed to go on active duty again in Afghanistan, Kirk was required to sign a statement acknowledging he knew to avoid all political work.

"Commander Kirk was counseled about each of his violations after they occurred and signed a statement acknowledging the limitations on his ability to participate in campaign activities while on active duty. He was required to complete this acknowledgment before being allowed to begin active duty in December 2009," the Pentagon said.