Republican candidate for U.S. Senate Dan Sullivan tours the ASRC Energy Services facility and campaigns on the Kenai Peninsula in Soldotna, Alaska, on Oct. 4, 2014. (Melina Mara/The Washington Post)

What seems to get Dan Sullivan most excited is putting on a neon hard-hat and safety goggles, zipping up a reflective vest and talking about Alaska’s vast energy potential.

“It’s just cranking,” Sullivan, the state’s Republican nominee for the U.S. Senate, said as he led a reporter on a tour of a fabrication facility and giant platform dock jutting into Cook Inlet.

The inlet, off Alaska’s scenic Kenai Peninsula, boasts one of the country’s richest deposits of oil and natural gas, yet development here all but dried up a few years ago. As Sullivan tells the story, it took Republican state government leaders — namely a natural resources commissioner by the name of Dan Sullivan — to get Cook Inlet booming again by luring companies with land deals.

“We went on a very aggressive tear, and this basin has come alive,” Sullivan said. The liquefied natural gas facility? “Monster.” The fertilizer plant? “Big.” Has Sen. Mark Begich, the Democrat whom Sullivan is trying to unseat in one of the country’s most competitive midterm races, played a role in reviving Nikiski? “No,” Sullivan said. “No, he has not.”

He continued like this for 90 minutes. (“I’m just trying to school him,” he told his hosts, referring to a Washington Post reporter.)

Dan Sullivan tours the ASRC Energy Services facility and campaigns on the Kenai Peninsula in Soldotna, Alaska, on Oct. 4, 2014. (Melina Mara/The Washington Post)

Sullivan, who began his political career working on President George W. Bush’s National Security Council staff and at the State Department as an assistant secretary, wants a new title in the federal government. But he’s preaching a gospel of diminished federal power, arguing that regulations stymie growth.

At campaign stops, Sullivan repeats this catchy phrase: “More freedom, less government.” He argues that President Obama’s administration has been a case study in federal overreach — and that Begich has enabled the feds rather than fighting them.

Begich’s campaign countered that Sullivan’s anti-federal rhetoric rings hollow, in part because Sullivan shared responsibility for controversial government surveillance programs launched under the USA Patriot Act. Begich has been a vocal critic of those programs, which he says violate people’s privacy rights.

For Sullivan — who could help the GOP take control of the Senate by winning in November — the challenge is linking Begich to Obama, who is deeply unpopular in Alaska. Through six years in office, Begich has branded himself as an independent voice. As he said to The Post this year about Obama, “I’ll be a thorn in his [posterior].”

On energy issues, Begich has a record of backing industry development despite environmental objections. He signed letters with Republican lawmakers urging the Energy Department to expedite permit applications for liquefied natural gas exports. Begich pressed regulators to allow ConocoPhillips to build a bridge in a sensitive area so the company could drill in the National Petroleum Reserve. He also helped Shell Oil obtain federal permits to drill in the Arctic Ocean.

In an interview, Begich said he has been “carrying Alaskan values to Washington, D.C.” He noted that before he took office in 2009 — when Alaska’s congressional delegation was all-Republican and the Bush administration was in power — drilling projects were stalled. “Arctic oil and gas is now moving forward,” Begich said.

Like many GOP challengers running against Democratic incumbents, Sullivan is trying to frame the election around Obama and Senate Majority Leader Harry M. Reid (D-Nev.). During a pep talk at his campaign office in Soldotna, Sullivan told supporters, “Imagine the last two years of Obama with Harry Reid in charge, how much damage could happen to this country. We need to beat Mark Begich, retire Harry Reid and start taking this country back!”

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Sullivan is betting that in a state where Obama lost to Mitt Romney by 14 percentage points in 2012 — and where the number of registered Republicans is nearly double the number of registered Democrats — a partisan message will carry the day.

“I don’t know that I’m against Mark Begich, but I’ve been a Republican all my life,” Dale Bagley, 50, who owns a real estate company, said in Soldotna. “I felt like for six years, we’ve lost a valuable seat there that should belong to a Republican.”

Polling in Alaska is notoriously unreliable, but recent surveys have given Sullivan a lead of three to six percentage points.

To compensate, Begich is investing heavily in a sophisticated field organization to drive up turnout among likely supporters. Begich also is counting on three ballot measures — to legalize marijuana, to increase the minimum wage and to ban mining in Bristol Bay — to motivate Democrats and left-leaning independents to vote.

A consistent theme for Begich, 52, is his Alaska roots. He was born in Anchorage and is a son of a well-liked congressman who died in a plane crash while in office. Begich’s television ads show him flying in a tiny prop plane through mountain passes, riding on a fishing boat and driving a snowmobile in a temperature of 20 degrees below zero. His campaign slogan is “True Alaska.”

Sullivan, 49, was born and raised in Ohio and spent portions of his adult life in the Washington area, leading Democrats to dog him with questions about his residency. From 2006 to 2008, during his service in the Bush administration, Sullivan considered Maryland his primary residence and received property tax breaks there while still voting in Alaska.

“You need to understand Alaska, and you need to actually know how long you’ve been here,” Begich said in the interview. “He’s not been able to pinpoint that exact day or month or year.”

Sullivan accused Begich of focusing on “small-ball things.” He said he married his wife, an Alaska Native, 20 years ago and moved to the state three years later once he finished an active-duty tour in the Marines. His daughters were born and raised in Alaska, he said, and he left the state only to deploy overseas and work at the State Department.

“Even when I was gone, I was still serving my fellow Alaskans,” Sullivan said. “I was just doing it from places like Baghdad and Kabul and Pakistan and Washington, D.C.”

Sullivan added, “Please write this down: Mark Begich is making this campaign about, well, ‘Dan Sullivan wasn’t born here and I was.’ Mark Begich [is] the poster child of why that issue doesn’t matter.” He argued that Begich has been Alaska’s least effective senator, while the late Ted Stevens (R) — who was born in Indiana, served in the military and worked in Washington before moving to Alaska at age 30 — had been its most effective one.

In Alaska, where dynamic, headline-grabbing characters have filled the Republican stage over the years — Stevens, former governor Sarah Palin, Rep. Don Young and tea party-backed former Senate candidate Joe Miller — Sullivan stands out for his relative blandness. He is also disciplined, which makes him a favorite among party leaders in Washington.

During the tour in Nikiski, Sullivan introduced himself to a welder named Ray Stichal and asked for his vote. “Keep it cranking,” Sullivan told him. “I’m proud to say I helped drive a lot of this.”

Sullivan offered another reminder: “Four years ago, a ghost town. Boarded-up places. Right now, smoking hot.”