THEY sang her praises with a country music twang in Nashville yesterday, but not even the sugary lyrics of a specially written Sarah Palin song — Change You Won’t Regret — could hide the tensions between the former Alaska governor and the dyspeptic conservative rabble-rousers collectively known as Tea Party Nation.

As the keynote speaker at the first national convention of the right-wing grassroots activists shaking up Republican politics, Palin was assured of an international spotlight last night as she paid tribute to the “everyday Americans” and “likeminded folks” who have turned anger and frustration at government policies into a 21stcentury revival of the Boston tea party revolt of 1773.

Palin’s paid appearance at a showcase for right-wing rebellion spurred fresh controversy about her political intentions and her relations with a Republican party establishment which is desperate not to derail its chances of ousting President Barack Obama after only one term.

Explaining her enthusiasm for the Tea Party activists last week, Palin praised their “patriotic indignation” and “commonsense conservative policies and values”. She also pledged to attend further rallies in Nevada next month and in Boston in April.

Yet even as she was expressing solidarity with activists fighting against an “out-of-touch political establishment”, it emerged that she had agreed to campaign in Arizona next month for Senator John McCain, her former presidential running mate on the 2008 Republican ticket. McCain is facing a dangerous Senate re-election challenge from the former congressman JD Hayworth, a conservative darling of the Tea Party movement.

After months of acrimony between the McCain and Palin camps over who was more to blame for their defeat by Obama, Palin has evidently decided that the hatchet should be buried — and not in McCain’s back.

Yet her decision to endorse a notoriously moderate Republican stalwart over a Tea Party favourite drew gasps of dismay and a flood of bewildered complaints to Palin’s Facebook page, which has almost 1.3m readers. “I’m extremely disappointed that you would campaign for John McCain,” wrote Patricia Brown, one of her Facebook fans. “He is not a conservative. It makes me wonder if you really believe what you say.”

The Texan tea set have also been stunned by Palin’s support for Governor Rick Perry, who is running for re-election this year. Perry is being challenged by Debra Medina, a former nurse and businesswoman and an early Tea Party campaigner.

“I can’t believe you are backing Perry,” said Christi Cameron, a Medina supporter. “Something is wrong.”

The fuss underlined both the fragile state of the fledgling Tea Party movement, which remains riven with policy disagreements over how its revolt should be managed, and the contradictory pressures of Palin’s widely expected presidential ambitions.

Is she buttering up the party because she intends to run for the White House as a Republican? Or will the Tea Party provide a launchpad for an independent bid? For all its chaotic quarrelling and reckless rhetoric — one speaker warned Americans they would be “boiled to death in the cauldron of the nanny state” — a convention organiser insisted that “people of quality and maturity” were emerging to lead it.

For Republican grandees scenting a comeback after the fiasco of Obama’s imploding healthcare reforms, Palin and her teatime antics represent either an opportunity or a threat, and few have decided which it is.

Even as the Tea Party was drawing up plans for a formal committee that will raise funds and direct support to conservative candidates, senior Republican officials were announcing a scheme of their own to create a new right-wing think tank that will help design the party’s future policies.

The soon-to-be-launched American Action Network includes party heavyweights such as Jeb Bush, brother of George W and a former Florida governor; Haley Barbour, the governor of Mississippi; and the former senator Norm Coleman from Minnesota.

Republican officials recognise that the enthusiasm and commitment of the Tea Party activists could prove a beneficial factor in future elections. Yet many also worry that the Tea Party image of belligerent extremism may alienate middle-of-the-road voters who might be regretting their support for Obama last year.

From the “moose-shootin’ mama” from Alaska — also described in song as “the shining light on the right that the left just doesn’t get” — there was only polite evasion last week as Palin kept the world guessing about her political intentions. The nearest she came to a hint was: “It’s important to keep faith with people who put a little bit of their faith in you.”