Arizona’s Republican delegation is doubling down to help support Sen. John McCain (R-Ariz.) in his primary battle against former Rep. J.D. Hayworth.

Senate Minority Whip Jon Kyl (R-Ariz.) is featured is a new 60-second radio ad, airing in select markets statewide, touting McCain as a strong advocate for the state.

“No one fights harder than John McCain — on health care, on national security, on stopping the terrible spending binge this president and the Democrats are on — John never stops. Never takes no way for an answer. It’s how he’s lived his life,” Kyl says in the radio spot.

Arizona’s entire GOP delegation has endorsed McCain’s re-election bid.

The ad launch comes a day after Rep. John Shadegg (R-Ariz.), went after Hayworth, dubbing him an earmarker in a radio interview with MSNBC host Joe Scarborough, a former Congressman who served with both Shadegg and Hayworth.

Asked by Scarborough whether Hayworth was a conservative, Shadegg said, “He had a fairly conservative voting record when he was in the House, but he was an earmarker, Joe.” Shadegg and Scarborough then reminisced about Hayworth siding with then-Speaker Newt Gingrich (R-Ga.) against them in the battle over limiting earmarks in the 1990s.

“Newt called us ‘jihadists’ and I remember our friend J.D. Hayworth standing up in those caucus meetings and just beating the hell out of us,” Scarborough recalled. “And all we were trying to do was balance the budget.”

Yet, as Scarborough noted, “they love him in the ‘tea party.'” And that could be a factor in the Aug. 24 primary.