Clinton called caucuses "creatures of the parties' extremes" in a January 22, 2012, email to confidante Sidney Blumenthal.
That email was among a new tranche released Monday by the State Department as part of its ongoing effort, under a judge's order, to make public the former secretary of state's work-related emails.
On Wednesday, Lily Adams, the Clinton campaign's Iowa spokeswoman, knocked some of the criticism the candidate has received -- most of which has come from Martin O'Malley's presidential campaign -- as "flat out wrong."
"From day one of this campaign, Hillary Clinton has been committed to earning the support of every Iowan in February's caucus -- any suggestion otherwise is just flat out wrong," Adams said. "That's why she made her first stop of this campaign in the Hawkeye State and why she continues to meet with Iowans in town halls, coffee shops, and living rooms to discuss her plan to build an America where everyone can get ahead."
O'Malley's campaign has hit Clinton repeatedly for the email, labeling the comments "disparaging" in an email to reporters and called on the former secretary of state to clarify her position. But the former Maryland governor has also questioned the caucus process.
"If I had my wish, I wish that every state had a primary so more people could vote, rather than have caucuses," O'Malley said during an interview with ABC in February 2008. At the time, he was a Clinton supporter and defending her after losses in the Washington State and Nebraska caucuses.
"Well, I'm biased towards primaries," O'Malley said. "I mean, caucuses, there's so very, very few people that, I mean, relatively speaking that show up for caucuses. I'm inclined towards primaries."
George Appleby, O'Malley's Iowa co-chairman, did not say whether the former governor still holds the views he described in 2008.
Appelby instead emphasized that his candidate had worked the 1984 Iowa caucuses for Sen. Gary Hart and was currently "campaigning the Iowa way." "I worked with Gov. O'Malley during the 1984 Iowa caucuses, and he knows firsthand what a critical role they play in the nominating process," he said.
States vote on presidential nominees through primaries -- where residents cast their ballots as they would in a general election -- or caucuses, where voters gather, talk and openly decide who to support. In some states there are rounds of elimination to cut out the lowest-performing candidates. It's a process that lends an edge to the best-organized candidates with the most passionate supporters.
Clinton lost the 2008 Iowa caucus to then-Sen. Barack Obama. In 2004, Howard Dean was damaged by similar comments -- but those were captured on video, rather than in an email.
Clinton's email to her friend Blumenthal also includes nicknames for two of the Republican front-runners from that election cycle -- Mitt Romney and Newt Gingrich -- as well as analysis on how their neck-and-neck race would play out.
"If Mittens (Mitt Romney) can't beat Grinch (Gingrich) in Florida, there will be pressure on state Republican parties to reopen or liberalize ballot access especially in the caucuses, which as we know are creatures of the parties' extremes," Clinton wrote.