LARAMIE, Wyo. — The Cowboys were playing at home on a recent Saturday, which meant a big crowd, which meant Mike Enzi was outside the University of Wyoming football stadium, looking like an elderly but still popular homecoming king.

Fans in brown and gold strode up to the state's senior U.S. senator to slap him on the back, offer an arm-pumping handshake or make small talk about farming, kids' soccer and his recent radio interview on the Middle East.

At 69, Michael B. Enzi is the epitome of unassuming, a figure widely known and liked at home but scarcely seen or heard outside Wyoming or beyond Capitol Hill, even after more than 16 years in the Senate. It is a career in the Washington shadows that might have happily persisted but for a surprise challenge in next year's contest from his flame-throwing Republican primary opponent: Liz Cheney, the eldest daughter of former Vice President and Wyoming congressman Dick Cheney.

After spending the last several decades away — working in the George W. Bush administration, helping write her father's memoir, delivering commentary on Fox News — Liz Cheney bought a log home with a view of the Tetons, enrolled her four youngest children in public schools and picked a fight that few here, save vastly outnumbered Democrats, are happy to see.

In just 2 1/2 months as a declared candidate, Cheney has generated more controversy and national headlines — about a tardy tax bill, a family divide over same-sex marriage, a fishing license scandal, an attack on the newspaper industry — than Enzi has managed in a 40-year career, going back to his days as mayor of Gillette.

There is little substantive difference between the two candidates. Both are deeply conservative and virtually certain to keep the seat in Republican hands, regardless of who wins the August 2014 primary. So their contest has become a test of celebrity versus familiarity, of brashness versus understatement and, as Washington lurches from one partisan showdown to the next, the question of when compromise equals capitulation.

Voters "expect results out of Washington," Enzi said, pausing between handshakes at the football stadium, "not just a bunch of poking a finger in the chest of the other person and out-shouting them." Cheney calls that "going along to get along."

Enzi seemed genuinely startled when Cheney, 47, announced her candidacy in July, just half an hour after he declared his plans to seek a fourth term. "I thought we were friends," Enzi lamented to reporters. (The senator has fly-fished with the former vice president.)

But Cheney's ambition, if not her timing, was no secret. Even before she bought a home last year in the posh Jackson Hole area, she was making the rounds of Rotary Club meetings, Republican fundraising dinners and Wyoming tea party gatherings.

She speaks in near-apocalyptic terms about the direction of the country under President Obama — the most radical man, she says, ever to sit in the White House — and suggests Enzi has been insufficiently resolute in fighting back. She cites, as a case in point, the months the senator spent in bipartisan talks on healthcare legislation before voting against the finished product.

"A nice man," she said dismissively during a recent radio interview on Casper's KTWO. "I think it's just, frankly, time to say we need a new approach."

For all her pugnacity, however, Cheney has spent much of the early campaign on the defensive.

She was late on her property tax bill because, she said, of a misunderstanding about the terms of the sale. She sparked a family squabble by declaring her opposition to same-sex marriage. "I love my sister," responded Mary Cheney, who is gay and married to a longtime partner. "But she is dead wrong."

Perhaps most significantly, it was revealed that Liz Cheney received a state fishing license 72 days after closing on her Wyoming home, a violation of the law requiring residents to live in the state 365 consecutive days. Cheney blamed a clerical error and slammed the newspaper editor who reported that she paid a $220 fine.

"Newspapers are dying, and that's not a bad thing," she told a tea party gathering. "We're not depending on the Jackson Hole News & Guide to get the news out. We're depending on ourselves. We're going over their heads."

Small as it may seem, the matter of an illegitimate fishing license played into a larger, far more troublesome issue facing Cheney: the notion that she parachuted into Wyoming for the sole purpose of seeking elected office.

Although she attended elementary and junior high school in Casper and calls herself "a fourth-generation Wyomingite" — citing family who settled in the state in 1907 — Cheney graduated from high school in northern Virginia, college in Colorado and law school in Chicago. Until moving back, she and her family lived in the Washington, D.C., suburbs.

Cheney, whose campaign did not respond to multiple phone calls and emails, dismisses the residency issue as a diversion. But it came up repeatedly, unprompted, in conversations with voters.

"She's been here a year and she's running for the Senate?" said Paul Suchor, his voice edged with sarcasm. The 56-year-old construction worker first met Enzi and his wife in the 1970s, back when the couple sold shoes from the family store in downtown Gillette.

"How can she know what's right and wrong for the state if she hasn't lived here the last 20 years?" Suchor said. "I really think she's running off her father's name."

Laurie Wagner, 59, whose husband runs one of the TV stations in Cheyenne, said Cheney touting her family's Wyoming roots was "all well and good," adding, "I understand that. But she hasn't been here in a while."

Like many, Wagner has met Enzi several times. It's not hard in a state with fewer than 600,000 residents. One teacher in Casper said she and the senator had spoken about education on numerous occasions. An oil industry worker from Evanston remembered Enzi showing up 10 years ago for a scholarship dinner for his son, and the three of them discussing the Harry Potter books.

"I'm kind of favorable to him because he was at that celebration and we got to talk a little bit," said Dennis Anderson, 63, a draftsman and document manager for Chevron.

In modern times, no senator from Wyoming has completed more than three terms, making Enzi's try for four something of a reach. Still, with no great agitation for change, the burden is on Cheney to explain why the incumbent deserves to be kicked out of office.

"That's hard to do when people feel they know Enzi," said James King, who teaches political science at the university in Laramie. "And they like Enzi."

mark.barabak@latimes.com

"That's hard to do when people feel they know Enzi," said James King, who teaches political science at the university in Laramie. "And they like Enzi."

mark.barabak@latimes.com