Sen. John McCain wants to call in the cavalry to defend Arizona from illegal immigrants crossing the border from Mexico�and to shore up his own right flank.

McCain asked the Obama administration Monday to send National Guard troops to the border after a prominent Arizona rancher was found shot to death on his own property.

Rancher's murder fuels firestorm

"I am asking you and the administration to immediately reconsider your position and send National Guard troops to our southern border region," McCain wrote in a letter to Homeland Security Secretary Janet Napolitano. Last year, the administration denied a request from Arizona Gov. Jan Brewer for National Guard protection for the border.

McCain supported comprehensive immigration reform during the Bush years�legislation that would have provided a path to citizenship for the more than 10 million immigrants currently living in the U.S. illegally. The position angered many on the right, but it's a position he's backed away from in the face a stiff primary challenge from former Rep. J.D. Hayworth. Hayworth, a darling of Tea Party activists, has repeatedly attacked McCain as wrong on immigration.

The Arizona Republic is a member of the Politico Network.