TUCSON, Ariz. - Sarah Palin lent her star power among fellow conservatives to former running mate John McCain in his tough Senate re-election campaign, telling a rally Friday that McCain pegged President Barack Obama right when he said the Democrat would swell the size of government.

McCain is facing the hardest election fight of his Senate career as he fends off a Republican primary challenge from the right. J.D. Hayworth, former congressman and conservative talk radio host, says McCain is too moderate for Arizona Republicans. Hayworth has tried to build support among conservative activists who identify with the tea party movement.

Palin, among the most popular figures with those activists, appeared with McCain for the first time since the pair lost the 2008 presidential election.

"Everyone here supporting John McCain, we are all part of that tea party movement," Palin told the rally.

As the former Alaska governor took the stage with McCain, some in the crowd of 4,000 chanted, "Sarah, Sarah," not the name of the man who just a year and a half ago topped his party's ticket.

Palin said McCain warned the country that Obama's policies would increase the size of government and the debt, and that the signing this week of a health overhaul law proves McCain right.

McCain called for repeal of the health law, which Republicans are challenging in court and plan to make a leading issue in congressional elections.

"There's something going on out there, my friends," McCain said. "It's a revolution. It's a peaceful revolution, but we're going to take on this Obamacare."

Palin took heat this week when she released a list of 20 U.S. House seats she said conservatives should try to win in the November elections. The list, posted on her Facebook page, featured a U.S. map with circles and cross hairs over the 20 districts. She also sent a tweet saying, "Don't Retreat, Instead - RELOAD!"

Critics said it was inappropriate to use gun imagery, especially as some Democrats who supported the health care overhaul reported receiving threats of violence.

Palin called it a "ginned up" controversy and defended her rhetoric.

"When we take up our arms, we're talking about our vote," she said.

Palin said the Republican Party needs new blood and new leaders, "but we also need statesmen and heroes like John McCain in there to help us get through these challenging times."

Hayworth has tried to define himself as "the consistent conservative" in contrast to the "maverick" McCain.

Palin was a first-term governor of Alaska when McCain plucked her from relative obscurity to be his running mate. She went on to become a conservative draw and leading Republican critic of Obama and the Democrats in Congress.

Before Hayworth left his radio show to enter the race, he used the airwaves to attack McCain's congressional record, most notably his work with the late Sen. Edward M. Kennedy on a bill that would have created a pathway to citizenship for illegal immigrants.

About a half dozen Hayworth supporters gathered outside McCain's rally and were unimpressed with Palin's support for the senator, saying she is helping McCain because he launched her national political career.

"It's disappointing, but a lot of us understand it's just political payback," said Jennifer Leslie, 41, of Oro Valley, Ariz. McCain is "calling in his favors."

Leslie carried a sign that said "Sarah supporter for JD Hayworth" and wrote "JD" on her hand.

McCain and Palin were raising money Friday night at the same Phoenix hotel where they conceded the presidential election, and planned a rally today in the Phoenix suburb of Mesa.

Palin has admonished McCain's presidential campaign since their loss, citing tension between her advisers and McCain's. She said she was kept "bottled up" during the campaign and prevented from delivering a concession speech Election Night. She has not criticized McCain himself, however, and the senator has stood by his decision to choose her as his running mate.