Washington (CNN) - As Sen. John McCain readies for a potential primary challenge from the right this fall, the Arizona Republican is playing his trump card.
Sarah Palin, McCain's former running mate and perhaps the most powerful brand in Republican politics, will stump for McCain in Arizona on March 26 and 27, a Palin adviser told CNN. The presence of Palin - and the considerable crowds and media attention she will draw - might give pause to J.D. Hayworth, the former Republican congressman and radio host who opposes McCain's position on illegal immigration and is mulling a Senate run of his own.
The former Alaska governor will also hit the campaign trail in the coming month for two conservative heroes - Texas Gov. Rick Perry and Minnesota Rep. Michele Bachmann.
Palin has already endorsed Perry in his primary fight against Texas Sen. Kay Bailey Hutchison; she will appear with the governor in Houston on Feb. 7.
Palin and Bachmann, meanwhile, will team up on April 7 in Minnesota.