Neil Chatterjee, Catrina Rorke, Seth Stein and Diane Regas are profiled.

Neil ChatterjeeHelping Mitch McConnell make coal a burning issue for the White House.

Neil Chatterjee is the senior energy advisor for Senate majority leader Mitch McConnell. (Chet Sussli)

It is a Tuesday afternoon in June, and over lunch in the Senate Dining Room, Neil Chatterjee, a senior energy policy adviser to Senate Majority Leader Mitch McConnell, is telling me about the time he wrote a high school paper about his boss. McConnell had just swept into his second term in the upper chamber and was already being talked about in conservative circles as a rising star in Washington. Chatterjee, who's from Kentucky, recalls painstakingly researching the lawmaker's life and career, and coming to admire him for fighting for the people of his state.

He says he knew then that, one day, he wanted to work beside McConnell. "I've told him about it, and he wants to see the paper," Chatterjee says with a smile. "He wants to know what kind of grade I got."

Today, Chatterjee, 38, consults on key decisions the majority leader's office makes on energy, environment, natural resources, agriculture, transportation, and commodity futures policy. He has also become Mc-Connell's right-hand man in the fight against what Republicans scathingly call President Obama's "War on Coal"—a battle that is heating up as the administration gets closer to finalizing limits on carbon dioxide emissions from power plants, a move widely expected to trigger coal-plant shutdowns. McConnell has been working to take down Obama's environmental regulations for years, but when he became the majority leader at the start of 2015, he secured a powerful platform to set the agenda and shape the debate. Now, Chatterjee is helping him use that perch to advance his goals.

Chatterjee was raised in Lexington, where his parents worked as cancer researchers, but the coal industry supported many families he knew and was woven into the social fabric of the state. He attended Saint Lawrence University in New York, where he majored in sociology and psychology, and earned a law degree from the University of Cincinnati before arriving in Washington at the age of 26. His first gig was an internship with the House Ways and Means Committee, after which he landed a job in the leadership office of then-House Republican Conference Chairwoman Deborah Pryce of Ohio. He intended to work on health care policy, he tells me, but in Pryce's office he was asked to tackle energy instead. "It wasn't the plan," he says, "but I think because of my experiences in Kentucky, I took to it a lot faster. There was something innate that I think helped me grasp it quicker."

When Democrats took control of the House in 2006, Chatterjee left the Hill to work as a principal in government relations at the National Rural Electric Cooperative Association, a trade group representing consumer-owned rural electricity providers. There, he served as the association's liaison to Congress, advocating for ratepayers and pushing back against regulations that threatened to drive up the cost of electricity. "The type of folks I interacted with there, everyone from the distribution managers to the consumers, those were the people I grew up with. It was very easy to relate to, and it sort of tied everything together for me," he says.

After nearly three years at the association, Chatterjee's high school dream came true: In 2009, he went to work in Senator McConnell's personal office as a legislative assistant. "It wasn't even really a transition, because he was fighting the same fights on behalf of the same people I had been working for at the association," Chatterjee recalls. He quickly rose through the ranks, earning a promotion to senior policy adviser in the leadership office the following year. He says he enjoys the constant challenge and fast pace of his current job, but above all, he tells me, he enjoys working closely with the majority leader. "He's the smartest person I know," Chatterjee says. "I can't quantify how much I've learned just from observing him in action."

—Clare Foran

IN THE TANKSCatrina RorkeR Street Institute

Catrina Rorke is director of energy policy at the R Street Institute. (Chet Susslin)

As the new director of energy policy at the R Street Institute, a conservative think tank, Catrina Rorke hopes to persuade fellow conservatives that a tax on carbon pollution is sound policy. She knows that particular effort will be an uphill climb. But Rorke, 30, a Long Island native whose parents are both nuclear engineers, tells me she will also be advocating for policies that enjoy significantly more support on the Right, including cutting regulatory red tape and increasing natural-gas exports. "A big part of what I'm going to do is find ways to identify R Street as conservative on energy," she says. "It's helpful to be able to tell our friends that we agree with them 99 percent of the time." Rorke, a graduate of the University of North Carolina at Chapel Hill and Columbia University, joined R Street in April, after nearly four years at the American Action Forum, a "center-right" policy research group.

—Clare Foran

INTEREST GROUPSSeth SteinLeague of Conservation Voters

Seth Stein is the national press secretary for the League of Conservation Voters. (Chet Susslin)

Last fall, Seth Stein was in Ithaca, New York, serving as a one-man communications shop for Democrat Martha Robertson, who was trying to unseat Republican Rep. Tom Reed. After Robertson lost the election, Stein "slept for two weeks" and set aside some time to assess his next steps. In April, he took a big one: He became national press secretary for the League of Conservation Voters, a political advocacy organization that supports candidates it perceives to be pro-environment. "I wanted something a little more stable," Stein says of his new post. But that wasn't the job's main selling point. "I get to work on the policy stuff and the election," he says. "So it's great. It appeals to both the things that I like." A native of Chicago, the 26-year-old says his new job is a homecoming of sorts. Back in 2010, he worked as canvass director for the Oregon chapter of LCV for a campaign season.

—Lucia Graves

INTEREST GROUPDiane RegasEnvironmental Defense Fund

Diane Regas is the executive director of the Environmental Defense Fund. (John Rae)

Everybody wants a clean environment, for now and to leave for our grandkids," says Diane Regas. "It's a shared value." This May, Regas became executive director of the Environmental Defense Fund, a global nonprofit dedicated to advancing environmental solutions. Her job, as she sees it, is to help establish the organization's vision and to "play a connecting role between EDF and others"—including businesses, government entities, and green groups—to further goals that range from curbing climate change to reducing pollution. Regas, who's been with EDF for nine years, was formerly senior vice president for programs there. Before that, the 53-year-old from Denver spent nearly 20 years at the Environmental Protection Agency. She has also served as an environmental policy adviser to President Clinton's Domestic Policy Council and she cochaired President George W. Bush's interagency task force on oceans. She says she has "a lot of respect" for people on both sides of the aisle "who are committed to making progress on the issues."

—Lucia Graves