The political scene’s hottest commodity will be popping up in Phoenix and Tucson to campaign with Sen. John McCain (R).

Sen. Scott Brown (R-Mass.) has agreed to appear with McCain at a Friday rally in Phoenix and at a Saturday meet-and-greet in Tucson.

Brown, a GOP superstar since his upset special election victory in January, is the latest in a steady stream of backers McCain is bringing in as he tries to beat back a primary challenge from former Rep. JD Hayworth.

Scheduled to campaign for McCain later this month is former Alaska Gov. Sarah Palin, McCain’s vice presidential pick in 2008.

House Primary to Test ‘Establishment’ Label

The Republican primary in the Tucson-area 8th district is shaping up as a test of whether voters want an outsider or an “establishment” candidate.

Marine Corps combat veteran Jesse Kelly, who has been working hard to woo backing from “tea party” groups, sent an e-mail to supporters Wednesday that described a fundraiser of former state Sen. Jonathan Paton with “party insiders.”

The e-mail said Paton’s event would be attended by “the same crew who backed the establishment candidate in 2008.”

Until Paton got into the race, Kelly was considered the leading candidate to take on Rep. Gabrielle Giffords (D).

“Now they are up to their old tricks, promoting another big-spending, establishment candidate,” the e-mail continues. “We can no longer allow the Republican Party to be hijacked by a few insiders who keep picking candidates loyal to them and soft on the issues that matter to us.”

Kelly has struggled to raise the cash to be competitive with Giffords, pulling in a modest $272,000 since joining the race last spring. He ended 2009 with $179,000 in cash on hand, compared with $1.6 million for Giffords.

Paton’s campaign has not yet filed a financial report.