Rep. Michele Bachmann Rep. Michele Bachmann "decidedly does not" possess the judgment, the demeanor, and the readiness to be President, writes Ron Carey, her former chief of staff, in a scathing op-ed in today's Des Moines Register.

Carey said the GOP presidential candidate ran disorganized campaign and congressional offices that were not responsive to constituents — leaving thousands of pieces of mail unopened and awaiting replies.

"If she is unable, or unwilling, to handle the basic duties of a campaign or congressional office, how could she possibly manage the magnitude of the presidency?" he wrote.

Carey, who was also the Minnesota GOP chairman during Tim Pawlenty's term as governor, says Republican voters need a candidate with experience in order to defeat President Barack Obama — namely Pawlenty.

"We need to look at the experience and accomplishments of the candidates and make sure we support someone who can not only defeat President Obama, but someone who also has the proven experience and leadership to handle the difficult challenges of the presidency," he said. "[Bachmann] is not prepared to assume the White House in 2013."