"If this is geared for her run for the presidency in 2012, it is one of the most politically tone-deaf decisions that we've seen," said Stuart Roy, a Republican consultant.
Iowa Sen. Chuck Grassley, a Republican, said Sunday on CBS, "I would think, if you want to run for president -- and I'm not sure that's got anything to do with what she's doing -- that the forum of a governorship would be a better forum than just being a private citizen."
A former aide to McCain called Palin's decision, "one more odd decision in a series of odd decisions" that play into a negative image of the soon-to-be former governor.
Despite largely remaining out of sight since her announcement Friday, Palin has been active on social networking sites through the holiday weekend.
Palin posted a thank-you letter to her Facebook page Saturday, and, later, on her Twitter page, explaining the reasons for her resignation, and ending with a rallying cry.
"For months now, I have consulted with friends and family, and with the lieutenant governor, about what is best for our wonderful state. ... We have accomplished so much and there's much more to do, but my family and I determined after prayerful consideration that sacrificing my title helps Alaska most," it read.
"I am now looking ahead and how we can advance this country together with our values of less government intervention, greater energy independence, stronger national security, and much-needed fiscal restraint," the letter read.
"I hope you will join me," it said. "Now is the time to rebuild and help our nation achieve greatness! God bless you! And I look forward to making a difference -- with you!"
And while Palin said defending herself against ethics complaints in Alaska has cost the state around "two million dollars" and would cost her and her husband "more than half a million dollars in legal bills in order to set the record straight," she may continue to do it for free on Twitter.
"Critics are spinning, so hang in there as they feed false info," she tweeted Sunday morning.
ABC News' John Hendren, Kristina Wong and Kate Barrett contributed to this story.