Embarrassing revelations about her costly campaign wardrobe and bloopers about the vice president's job description are raising fresh fears that Sarah Palin is dragging down the Republican ticket.
New polls showed Wednesday that seven weeks after John McCain plucked the Alaska governor from political obscurity to be his running mate in the November 4 elections, Palin is seen as an increasing liability for Republicans.
The Wall Street Journal/NBC News poll found that Americans are less and less convinced she is worthy to serve as the country's number-two leader.
"Her numbers have plummeted in our poll ... what's more 55 percent think she's unqualified to serve as president if the need arises, which is a troublesome number given McCain's age," said NBC political director Chuck Todd.
The poll also puts the 72-year-old McCain 10 points behind his Democratic rival Barack Obama, and says that 47 per cent of those surveyed viewed Palin negatively.
It confirmed the findings of an ABC/Washington Post poll released earlier this month which found that six in 10 voters saw Palin, 44, as lacking the experience to be an effective president.
"A third are now less likely to vote for McCain because of her," the Post added.
After being found guilty of abusing her power as governor in the so-called "troopergate" scandal over the firing of her ex-brother-in-law, Palin now faces a second probe over whether she violated ethics rules in the affair.
A spokesman said Palin, the first woman to be picked to serve on a Republican ticket, had requested this subsequent inquiry, branding the first probe a "political witch-hunt."
Then on Tuesday the Politico website caused a stir by publishing financial records of the Republican National Committee showing it has spent more than 150,000 dollars on clothes for Palin since late August.
McCain-Palin campaign spokeswoman Tracey Schmitt slammed the media for focusing on "pantsuits and blouses" during the country's hard economic times, saying the clothes were always intended to go to charity after the campaign.
But the New York Times Thursday wrote the wardrobe "joined the ranks of symbolic political excess" and reported that many Republicans "expressed consternation publicly and privately that the shopping spree .... would compromise Ms Palin's standing as Senator McCain's chief emissary to working-class voters."
Palin was also lambasted this week for failing to correctly spell out the vice president's role on several occasions, including during the vice presidential debate with her Democratic rival Joseph Biden.
Responding during one television interview to a question sent in by an elementary school pupil about what the vice-president does, Palin again overstated the White House second-in-command's powers.
"They're in charge of the United States Senate, so if they want to they can really get in there with the senators and make a lot of good policy changes," she said.
The comment directly contradicted the separation-of-powers principle enshrined in the US constitution, under which the vice-president as president of the Senate has a casting vote in the event of a tie, but takes no other role.
McCain has staunchly defended his running mate against the slew of attacks, stressing she will be a valuable asset in his campaign goal of ridding Washington of political corruption.
But even staunch Republicans remain unconvinced.
Ken Adelman, a Republican hawk who served in top diplomatic and defense posts for presidents Gerald Ford, Ronald Reagan and George H.W. Bush, told the New Yorker magazine that Palin's choice for vice president made him switch sides and he is now supporting Obama for president.
Former secretary of state Colin Powell, a Republican and military general who has also served as chairman of the joint chiefs of staff, on Sunday endorsed Obama and said of Palin: "I don't believe she is ready to be president of the United States, which is the job of the vice president."
And one of former president George HW Bush's speechwriters, Christopher Buckley, a prominent conservative, announced this month he was abandoning support for McCain for many reasons, including "the Palin nomination. What on earth can he have been thinking?"