She may feel vindicated by the US midterms, but others believe Palin proved a liability on a night of historic wins for her party

There was no way Sarah Palin was going to see the election results as anything other than a "big darn deal" for Tea Party conservatives, Mama Grizzlies and – of course – her personal political brand.

Her first tweet of the new Republican era, sent just after midnight, said (in full): "As always, proud to be American! Thanks, Commonsense Constitutional Conservatives, u didn't sit down & shut up … u refudiated extreme left."

But by dawn, television commentators were arguing that rather than "refudiating" the extreme left, Palin may have been the spoiler that cost the Republicans the Senate on a night of historic gains.

There was also speculation that establishment Republicans, having harnessed the energy of Tea Party activists to take the House of Representatives with a historic 60-seat pickup, would now be looking to ensure Palin does not cost them an even bigger prize: the White House in 2012.

Palin's election-night scorecard was mixed. Her top Tea Party favourites – Christine O'Donnell in Delaware and Sharron Angle in Nevada – lost after dislodging more mainstream, and arguably more electable, candidates in the Republican primaries. Those defeats helped the Democrats keep the Republicans from taking the Senate.

Palin could not elect John Raese, the Republican contender in West Virginia, despite making a personal last-minute appearance in a conservative coal state deeply hostile to Barack Obama's energy agenda.

She could not even ensure victory for her fellow Alaskan Joe Miller. Palin escalated a family feud with the Alaska branch of the party, engineering the primary defeat of Senator Lisa Murkowski. But by yesterday morning, Murkowski was still hanging on, with a dogged challenge as a write-in candidate.

From her perch at Fox News, where she did election night duty as commentator, Palin would admit to seeing only wins. "It's a big darn deal," she said, going on to compare the scale of the Republican victory to an earthquake.

She waved away earlier predictions by the Republican operative Karl Rove that elevating O'Donnell was a disaster that would cost the party a sure seat.

"Christine's defeat, of course, in a deep blue state, it's not really a surprise – disappointing for those who really wanted to shake it up in that state though," Palin said. "There was never any guarantee that a hardcore conservative would win in a deep blue state like Delaware."

But there were enough victorious Mama Grizzlies to solidify Palin's self-appointed role as king- or queen-maker. Kelly Ayotte won her Senate seat in New Hampshire. In gubernatorial races, Nikki Haley of South Carolina, Susan Martinez of New Mexico, and Mary Fallin of Oklahoma ushered in a new generation of Republican women leaders.

Palin could also claim some credit for eroding the Democrats' traditional gender advantage. Obama lost women's votes in droves on Tuesday night.

Those advantages were not lost on Republicans, even those who have clashed ferociously with Palin in the past.

"Without the energy of the Tea Party, we wouldn't be looking at Speaker Boehner," Nicolle Wallace, a senior John McCain aide who has had a number of high-visibility clashes with Palin, told MSNBC television. "Republicans accept we made some tradeoffs."

But maybe not for long. Palin's aggressive intervention in the midterm elections – and the mixed results – has refocused attention on her personal flaws as presidential material.

She may be a heroine to the Tea Party activists, capable of firing up the deeply conservative wing of the party. But she is poison to the broader electorate – in opinion polls, two-thirds still think she is unfit to be president – and she has shown she values ideological purity over electability.

That could present some conflicts further on to Republicans looking to build on their big gains in Congress before the 2012 elections. Palin made it clear yesterday that she is expecting payback, and that Republicans can not take her or the Tea Party activists for granted.

"They have the GOP establishment on notice right now, saying: 'We are going to hold you accountable,'" she said. "We cannot compromise, especially when it comes to taxes and overregulation. The Tea Party movement has got to grow beyond tonight. We have to look at the next election. We don't stop; we don't slow down."