For all the money and spin involved in special elections, the outcome rests heavily on the quality of the candidates.

That’s why Democrats have called in Seth Pendleton for the party’s four recent special elections in New York and Pennsylvania, including last month’s upset in New York’s 26th district.

Pendleton, 47, is the former director of training at the Democratic Congressional Campaign Committee. Helping candidates stay on message in debates, in interviews and on the stump is the crux of what he does, but Pendleton said the key to being a successful candidate is simply being authentic.

“Sometimes, yes, my job is to keep candidates from saying something that will blow up, that will make unintended headlines,” Pendleton said over lunch near his office in Washington, D.C.’s Chinatown. “After that triage — of making sure they know what they should and shouldn’t say — it’s figuring out the things that they say are true to them.”

Media training is something Democrats and Republicans alike say is invaluable for candidates. Firms such as HDMK and Pendleton’s 4C Partners, which was formed two years ago by four former DCCC staffers, offer media training as part of their range of services to campaigns and clients. Both major parties’ national committees contract with firms to provide training for candidates and staff.

“Campaigns can be well-funded and well-organized and well-directed, but they will succeed or fail on the power the candidate brings to the debate,” said HDMK’s Terry Holt, a Republican consultant. “The personal characteristics that come out — it’s all about tapping into what’s already there.”

Pendleton agreed. In Democrat Kathy Hochul’s victory last month in New York’s conservative 26th district, Pendleton and media consultant Jon Vogel, who also worked for Hochul, agreed the candidate started out with a lot to build from.

During their first conversation in training, Hochul explained to Pendleton that she was a “diner person” — that she made her campaign staff stop at every diner they drove by so she could just chat with folks.

“When you hear that, you know that this is a person that at the foundation level just likes people,” he said. “In the work I do, if they like people and they are comfortable talking about what inspires them and the things that are part of their personal narrative, that is a really hard combination to beat.”

Pendleton, the only Democrat among a family of seven growing up outside Philadelphia, said his mother has always used the abortion issue as her litmus test for candidates. However, she is also a big fan of Sen. Scott Brown (R-Mass.), who supports abortion rights.

He recently mentioned to her that by her own standards she would vote in a hypothetical matchup for Sen. Bob Casey (D-Pa.), who opposes abortion rights, over Brown.

“She looked at me, wrinkled her nose and goes, ‘No, I just like Scott Brown,’” he said. “That’s very powerful.”

Pendleton, who still lives in the Philly area, is a trained actor and member of the Screen Actors Guild and is credited in the 1994 movie “I.Q.” In 2004, he had a few months off from his master’s degree program at Harvard’s Kennedy School of Government and decided to volunteer on Democrat Ginny Schrader’s open-seat campaign in Pennsylvania’s 8th district. It was there he met Brian Smoot, who would later become his partner at 4C Partners.

They worked closely on media training on that campaign, and during the 2006 cycle, Smoot called Pendleton and asked him to join the campaign of now-former Rep. Ron Klein (D-Fla.).

By then Pendleton had formed KNP Communications with partners John Neffinger and Matt Kohut. The trio met at Harvard in 2004. KNP was founded out of frustration during the 2004 presidential election, when they saw Sen. John Kerry (D-Mass.), a decorated war veteran, painted as soft on national security. The firm has focused largely on media training and speaker training.

Pendleton and his KNP partners do regular work for the Progressive Talent Initiative run by Media Matters for America, a two-year-old program that puts up-and-coming liberal talking heads through a media training boot camp.

Following the 2006 cycle, Smoot was hired as DCCC political director and asked Pendleton to join him once again. Pendleton was hired in October 2007 to build and execute a new candidate training program at the committee. Pendleton traveled around the country in 2008, assisting Democratic House candidates from Alabama to Minnesota to Arizona.

Part of debate prep is strategy — knowing an opponent’s weaknesses and taking advantage of them. Pendleton said now-former Rep. Ann Kirkpatrick was able to fluster her opponent in Arizona’s 1st district that year, when Pendleton and her campaign team noticed Republican Sydney Hay did not respond well to direct questions from Kirkpatrick.

Pendleton likened the style of Kirkpatrick, who lost in 2010 and is running for her old seat in 2012, to the late Texas Gov. Ann Richards (D), whom Pendleton called the ultimate happy warrior. Richards was able to stick it to her opponents with a smile on her face.

After a second straight cycle of Democratic gains in the House, Smoot, Pendleton, Casey O’Shea and Nicole Runge left the DCCC to open 4C Partners in 2009. A few months later, Pendleton was coaching now-former Rep. Scott Murphy (D-N.Y.) in the 20th district special election. Murphy’s win was the first in a string of Democratic victories in competitive special elections that cycle that also included New York’s 23rd district and Pennsylvania’s 12th. Pendleton worked on all three.

“The candidates themselves matter a lot more, and Seth’s work is especially important in special elections, when there’s more of an intense media scrutiny on the candidates,” said Vogel, who was DCCC executive director last cycle. “Making sure the candidate is as sharp as possible during a debate and giving them the confidence to shine makes a big difference in these races.”

Pendleton believes nonverbal cues can be equally important to any answer a candidate gives during a debate. So he uses video as part of debate prep and training for interviews with the media. He plays the video of mock debates and interviews for candidates so they can study, critique and ultimately improve their own performances.

“I can talk all day long — do this or don’t do that — but when they see and hear how they look and how they sound, they tend to respond and say, ‘Oh, I should probably rethink that,’” Pendleton said.