WEST CHESTER, Ohio — Just outside Cincinnati, tucked among insurance agencies, hair salons and a yoga studio, is the nexus of one of the nation’s most mysterious networks pouring secret money into elections. “Langdon Law LLC Political, Election Nonprofit and Constitutional Law,” reads its small sign, which faces the building’s parking lot rather than the street. On a Tuesday afternoon last month, that parking lot was empty. No one answered the Langdon Law office door. Phone calls went unreturned. Unlike other heavy-hitting political lawyers, David Langdon doesn’t grandstand. But don’t overlook him. Langdon is a critical behind-the-scenes player among the small army of lawyers working to keep secret the origins of millions of dollars coursing through the American political system. Thanks to his work, this unremarkable suburb is a home base for nonprofits and super PACs that pour millions of dollars into elections. Langdon is also an unswerving legal warrior for conservative, often Christian, nonprofit organizations that together spend millions more to influence public policy and wield great influence among evangelical voters. Since the 2010 election cycle, at least 11 groups connected to Langdon or his firm have collectively spent at least $22 million on federal and state elections and ballot initiatives around the country, according to a Center for Public Integrity review of records. Two such groups, nonprofit Citizens for a Working America and a super PAC with the same name, combined to spend roughly $1.1 million on the 2012 presidential election alone. Langdon was a lead author of a state constitutional amendment defining marriage as between a man and a woman, which Ohio voters passed in 2004. The U.S. Supreme Court last month heard arguments on whether the Ohio ban on same-sex marriage is constitutional. He has donated thousands of work hours to Alliance Defending Freedom, which describes itself as a nonprofit Christian legal ministry and specializes in religious freedom cases. He also represents tea party groups suing the Internal Revenue Service over what they allege was unfair scrutiny of their applications for tax exemption, based upon their names and political views. Recently, he represented Susan B. Anthony List, a leading anti-abortion advocacy group, in a high-profile free speech case that reached the Supreme Court. Such outside groups and evangelical voters are both poised to play kingmaker roles in the 2016 elections, and Langdon — from the perennial presidential battlefield that is Ohio — is a point of convergence. This election cycle, the state is also the setting of a high-profile re-election bid by Republican Sen. Rob Portman, who in 2013 reversed his position to support same-sex marriage. Several conservative groups, including Citizens for Community Values, a longtime Langdon client, have vowed to defeat Portman. It won’t be easy. He has an $8 million war chest and a long list of endorsements, and a primary opponent has yet to emerge. The politically active groups linked to Langdon, several of which boast deep roots in Ohio, would be well positioned to wade into the 2016 elections. Langdon is “very influential, not very well known by the general public, but very well known in the dark shadows of politics,” said Ian James, executive director of Freedom Ohio, which advocates for a referendum to repeal the 2004 constitutional amendment banning same-sex marriage. “I have no doubt in my mind” that Langdon will be involved in the 2016 elections, he said. John Green, chairman of the political science department at the University of Akron, agreed. “I would not be surprised if a large portion of his network, if not all of his network, were active in Ohio in 2016,” he said. Who is David Langdon? Those who know Langdon describe him as focused and strongly committed to values rooted in his Christian beliefs. Langdon, now 44 and a father of six, attended the University of Akron Law School. Even then, nearly two decades ago, he was interested in litigation and politics and “really, really faith-based,” said Janeen Miller-Hogue, a colleague on the Akron Law Review during law school. “He’s just rock solid,” she said. “He’s black and white. We both don’t like the color gray. It’s a waste of energy.” Miller-Hogue said she valued his friendship in part because he could be trusted to keep a confidence. They lost touch after law school, she said, but added: “I bet if I called him today and I was in a pickle he’d be the first one to help.” Phil Burress, the head of Citizens for Community Values, said he first met Langdon through Langdon’s parents. Burress said he gave the young lawyer one of his early jobs. Throughout the late 1990s and early 2000s, Langdon’s name pops up in Ohio news stories tied to groups with socially conservative platforms. For example, he acted as a defense lawyer for abortion clinic protesters, filed a brief in another case on behalf of the Christian Coalition of Ohio and represented groups opposing a lesbian couple’s efforts to share equal custody of their children. In 2004, Citizens for Community Values had a prominent role in the effort for the constitutional amendment to ban same-sex marriage in Ohio, written by Langdon. Langdon disputed suggestions the ballot initiative was a bid to drive up conservative turnout to help President George W. Bush win Ohio, a hotly contested prize during the 2004 presidential election. “The reason I do what I do is to protect marriage,” he told The Washington Post at the time. In fact, Langdon, then and now a registered Republican, told the Post he hadn’t backed Bush in 2000. Instead, he supported Constitution Party candidate Howard Phillips. Getting the marriage amendment on the ballot was tricky, Burress said. In an undated online profile of Langdon, the Alliance Defending Freedom said Langdon and his then-law partner, Jeff Shafer, who now works for the organization, litigated nearly 50 cases in three weeks, fending off attempts to knock the amendment from the ballot. Voters approved the amendment, though a high-profile case challenging its legality is now before the Supreme Court. And Bush narrowly won Ohio, a critical victory that clinched his second term. Burress points to that battle as the one that made Langdon’s name. “Rightly or wrongly, the marriage amendment was given credit in 2004 for Bush winning Ohio, and David was the attorney who made that happen,” Burress said. Several of the groups linked to Langdon declined to talk about his work for them or how they found him. Burress, though, said he recommended Langdon to around 40 groups who work on similar types of issues, including CitizenLink, the advocacy arm of Focus on the Family. Burress also said Citizens for Community Values still works with Langdon. The Alliance Defending Freedom profile described Langdon as “one of the great veterans of the ministry’s war to defend marriage.” It said Langdon works with groups around the country on corporate, tax and regulatory issues and to “promote stricter government regulation of sexually oriented businesses.” Elected officials have also sought Langdon’s counsel. From 2005 until 2007, Langdon represented then-Ohio Secretary of State Kenneth Blackwell on election matters, including lawsuits related to voting machines and ballot access, and helped develop election law policy, according to his firm biography. Monty Lobb, Blackwell’s then-general counsel and chief of staff, said in an interview that he didn’t remember exactly how Langdon came to his attention, but they ran in the same conservative circles. The lawyer impressed him as a “bulldog” capable of providing detailed analysis of complex issues. Lobb said he appreciated that he and Langdon shared a common conservative Christian worldview, and he recommended him to Blackwell for an outside counsel job. Now a professor at Ohio Christian University in Circleville, Ohio, Lobb said Langdon delivered as promised and on budget. Once, he said, Langdon had promised to update him on a specific day, but the two wound up playing an epic game of phone tag. “He still made a point of trying to reach me and follow through at 11 o’clock at night,” Lobb remembered. “I don’t think it was anything earthshattering. That’s the kind of stuff that sticks with you. He could have waited until the next day and been fine with me.” In 2006, when Blackwell, a favorite of social conservatives, ran for governor, Langdon helped him select his running mate. He also wrote another ballot initiative for a constitutional amendment, this one on curbing government spending, on behalf of a group of which Blackwell was the honorary chairman. “He was competent, he’s principled, and I never had any bad experience when I worked with him,” said Blackwell, who said he hasn’t spoken to Langdon in more than three years but wouldn’t hesitate to recommend him. James, the Freedom Ohio activist, said he and Langdon actually worked together nearly a decade ago on a ballot referendum issue — the only time, he said, the two have found themselves on the same side of an issue. “I found him to be likable,” he said. “I thought he was very smart; I thought he was very strategic. For what it was, I thought he had a good sense of humor.” Still, he said, “It was very odd when he and I were on the phone together.” Burress said he doesn’t know everyone on Langdon’s current client list and can’t speak to the origin of the money going into elections. But, “if I saw his client list I could probably tell you there’s no one who represents or thinks differently than we do here,” he said. “His values are strong, and he’s not going to cross over it for money.” Burress said he’s currently working with Langdon on a project, but wouldn’t provide additional information. When asked whether he might work with Langdon on anything to do with Portman’s re-election bid, Burress replied, “I’m not going to discuss any of that.” Langdon isn’t going to, either. Langdon did not return telephone calls requesting an interview. When a Center for Public Integrity reporter knocked on the door of his Cincinnati house, Langdon told her to leave. “You’re not welcome here,” he said, calling approaching him at his home “unbelievably unprofessional.” Nonprofit central West Chester, Ohio, seems an unlikely place for a campaign finance and constitutional law practice to thrive. The suburb, population 60,000, is home to Republican U.S. House Speaker John Boehner, though there is no obvious connection between the two. Langdon Law’s offices — the practice includes at least one other lawyer — are about three miles from a family entertainment center claiming to have “the world’s largest indoor train display.” But the origin of the millions of dollars flowing through the nonprofits linked to Langdon Law isn’t exactly on the tourist maps. It is impossible to say where the money comes from, but the effect is real. Many of the groups in the network were formed in the wake of the Supreme Court’s 2010 Citizens United v. Federal Election Commission decision, which allowed corporations, unions and nonprofits to raise and spend unlimited funds to advocate for and against politicians. Nonprofits can’t have election-related activity as their primary purpose and need not reveal their donors, making them attractive vehicles for anonymous political spending. Such groups’ politicking has proliferated since the Citizens United decision, prompting accusations that some have been formed primarily to influence elections and calls for the IRS to more aggressively regulate them. Some of the groups have changed names. Donors to super PACs and ballot initiative groups have been publicly disclosed, but millions of dollars have flowed through nonprofits, obscuring the original source. Over the past three election cycles, groups connected to Langdon have transferred money among themselves, adding layers that make it even more difficult to track back to the source. The convoluted network “appears pretty clearly to be geared toward opaqueness,” said Robert Maguire, who investigates political nonprofits for the Center for Responsive Politics and has written about the groups. Langdon isn’t the only recurring character in this network. For instance, Norm Cummings, a former political director of the Republican National Committee who managed Blackwell’s 2006 gubernatorial bid, is on the board of New Models, a Virginia-based nonprofit that has given more than $2 million to groups with direct connections to Langdon since 2010 and paid Langdon Law $98,000 in 2010 in connection with an Ohio ballot issue. He’s also a director of nonprofit Citizens for a Working America, which received some of the money from New Models. At one point, Blackwell’s biography listed him as chair of Citizens for a Working America. In an interview, Blackwell said he had done “some speaking for Citizens for Working America … on issues associated with getting the economy moving again,” but he said he dealt with Cummings, not Langdon, and it was some time ago. Thomas Norris, an Ohio lobbyist, has been listed on tax filings as both the president and the executive director of the nonprofit Government Integrity Fund, which has given money to some of the groups connected to Langdon. He’s also chairman of the nonprofit Jobs and Progress Fund (Langdon is the treasurer and the group uses Langdon Law’s address). Norris told The (Cleveland) Plain Dealer he was involved in creating the Concrete and Portland Cement Action Network, a super PAC for which Langdon is the custodian of records. Joel Riter, a former aide to Ohio Treasurer Josh Mandel, has also been linked to several of the groups. On its most recent tax filing, Government Integrity Fund listed him as its chairman. He is also the treasurer of the Concrete and Portland Cement Action Network. Mandel, a Republican, ran unsuccessfully for U.S. Senate in 2012. Three groups with links to Langdon or his network — the Government Integrity Fund, super PAC Now or Never PAC and Focus on the Family-affiliated nonprofit CitizenLink — spent about $2.8 million on independent expenditures supporting Mandel and opposing his opponent, Democratic incumbent Sen. Sherrod Brown. Brown blasted groups that spend millions to influence elections but don’t publicly disclose their donors. “When a handful of billionaires are able to use their fortunes to exercise disproportionate influence on elections and mute the voices of working Ohioans, we have a problem,” Brown wrote in an emailed statement. “Citizens United opened the floodgates for such incredible sums of money to be spent on elections and we need to ensure that working Americans have just as loud a voice.” Cummings, Norris and Riter did not respond to requests for comment. ‘An excellent conservative lawyer’ A Center for Public Integrity review of federal and state election filings and nonprofit tax documents shows more than $1.3 million in payments from eight groups to the firm or Langdon since 2010. The money wasn’t all for work on elections. For example, ActRight Legal, a legal nonprofit with close ties to the National Organization for Marriage, paid Langdon Law about $119,000 for legal services in 2012, according to its federal tax filing. The payments to Langdon Law made up more than 10 percent of the group’s total expenses that year. Shawna Powell of ActRight Legal said Langdon was an independent contractor who worked on a civil rights lawsuit with several other firms, though she was not able to provide additional detail about it. She said his work with the organization has since ended. Cleta Mitchell, a Washington, D.C., lawyer and a board member of ActRight Legal, described Langdon as “a quality person and a good, smart lawyer,” but said her interactions with him had been limited. She otherwise refused to discuss him, referring questions to Langdon. CitizenLink reported paying Langdon Law about $176,000 for legal services between October 2012 and September 2013, a period that includes the 2012 election. CitizenLink spent about $2.6 million supporting Republican candidates running for federal office that year. The group declined to comment on its relationship with Langdon or the type of work he does for them. Langdon has also acted as local counsel for conservative watchdog group Judicial Watch in two cases, according to the group’s president, Tom Fitton. “I don’t know him personally but it sounds to me like he’s an excellent conservative lawyer and it should be no surprise that several of us are going to him,” Fitton said. “If any of those groups asked me for a lawyer in Ohio, David Langdon would be a lawyer I would recommend to them.” But without a referral, Langdon might be hard to find. Michael Beckel and Ben Wieder contributed to this story.