The attacks on Newt Gingrich have been as under-the-radar as they have been in-your-face.
Brochures and leaflets stuffed in mailboxes across Iowa call Gingrich a tree-hugging, Nancy Pelosi-loving, inconsistent career politician. And they've supplemented an onslaught of negative advertising on TV and radio, funded largely by allies of former Massachusetts Gov. Mitt Romney. It all has damaged Gingrich badly ahead of Tuesday's caucuses.
"I feel Romney-boated," Gingrich said Sunday, a reference to the Swiftboat Veterans for Truth ads that crippled Democratic presidential candidate John Kerry's 2004 campaign.
For all the hype about new digital-era campaign tactics, old-fashioned paper mail remains a potent campaign tool, with campaigns and outside groups alike using it heavily to promote their preferred candidates and undercut the others.
Here's why: It has a longer shelf life than television ads, which typically last 30 seconds or a minute at most. The glossy booklets lie around on coffee tables for voters to thumb through during commercials. They're easy to pull out when talking with neighbors.
For candidates, direct mail is relatively cheap to produce. And it allows campaigns to target individual voters with specific messages.
All that explains why Iowa Republicans have frequently returned home to find fliers and pamphlets in the mailboxes that reflect the bitter contours of this Republican nominating contest.
Mailers targeting Gingrich have focused on his support for legislation designed to curb manmade climate change, his joint appearance with Pelosi to push Congress to take action on it and the ethical allegations that cost him $300,000 to settle. Many have come from the pro-Romney super PAC called Restore Our Future, which his run by former Romney aides but is independent of his campaign.
"It's hard to know where Newt Gingrich stands on the issues," says one from the group that accuses Gingrich of flip-flopping on a series of matters and says Gingrich co-sponsored 418 bills with Pelosi in Congress. "Pelosi and Gingrich: More in common than you think."
Romney's campaign has stayed positive in TV ads but it hasn't pulled punches in direct mail and it has ramped up its spending on leaflets in recent weeks.
While some of his mail promotes his record as a venture capitalist and his family, much of it goes after Gingrich, including for appearing with Pelosi in an ad for an environmental group aligned with former Vice President Al Gore.
"When Al Gore needed allies ... they turned to Newt Gingrich," the mailing says.
Romney, himself, is hardly immune from direct-mail attacks.
"Romney is the second most dangerous man in America and will perpetuate Obama's slide into financial crisis," according to one mailer sent from the pro-Gingrich Strong America Now super PAC. "Don't let Romney backers mislead you!"
Often, campaigns with little money choose to spend their cash on mailers that are cheaper that pricy TV ads _ and can sometimes reach just as many people.
Rick Santorum, the former Pennsylvania senator who has been a footnote in the race until the past few days, went on the air for the first time in recent days.
By that point, 60,000 Iowans may have already gotten mailers in which he pledged he wouldn't "surrender" on social issues even though some Republicans have suggested that the best way to win back the White House is to call a truce on talking about topics like abortion, marriage, school prayer, and immigration."
Texas congressman Ron Paul, who enjoys strong support among his party's libertarian wing, sent mailers labeling Rick Perry and others "counterfeits" and promoted himself as a "true lifelong conservative." Paul also has mailed a seven-page letter to Christian conservatives discussing his opposition to abortion.
"As a doctor who has delivered over 4,000 babies, I know firsthand how precious, fragile and in need of protection human life is. That's why I am now, and have always been, pro-life," Paul wrote. "Maybe you didn't know this about me, since you and I both know the left-wing media likes to focus on their version of political stories."
Perry, the Texas governor hoping for a late-game surge, has criticized Gingrich and Romney on paper.
One of his mailers says Gingrich's record is "a story of insider access and million dollar paydays," criticizing his time after he left the speaker's office and made millions as a consultant.
The same mailing criticizes Romney for his work at Bain Capital, a venture capital firm that Perry says had a record of "killing jobs to maximize profits."
Outside groups, too, are looking to sway caucus-goers.
The National Right to Work Committee, which calls itself a nonpartisan organization, sent letters to Iowans asking whether Romney and Gingrich would work against "union bosses." It noted that Romney refused to answer the group's survey, and said: "Newt Gingrich's past opposition and Mitt Romney's vacillation are very troubling."
The group chose not to criticize Santorum with the same vitriol reserved for Romney and Gingrich despite his stance. Santorum opposes a national right-to-work push and instead favors a state-by-state approach to the issue. The organization, meanwhile, had nice things to say about Rep. Michele Bachmann of Minnesota, Perry and Paul.