In a wide slice of the Denver suburbs — including a city where one in five people is foreign-born — Democrats have not been able to edge out Republican U.S. Rep. Mike Coffman, who might as well be made of Teflon, according to political pundits.

Public-school students speak more than 160 languages in the district’s anchor, Aurora, a place where voters strongly favor Democrats.

In conventional political wisdom, the 6th Congressional District should have flipped blue long ago — the question on the national radar is if 2018 is the year it finally will.

Democratic challenger Jason Crow, in an election season over which Republican President Donald Trump looms large, hopes so. But analysts say Coffman has a strong foothold even in the more diverse parts of his district.

“Coffman’s political obituary has been written a number of times,” said Seth Masket, a political science professor at the University of Denver.

But Coffman, a military veteran who grew up in the heart of Aurora, has persisted against well-known Democratic challengers. He won the seat in 2008 and has been re-elected four times.

“I know the district,” said Coffman, rattling off a list of communities that include vegetable farmers and people of Indian descent focused on the U.S.’s high-tech visa program. “I certainly understand the diversity of the district.”

In addition to Aurora, the district includes south suburbs like Centennial, Littleton and Highlands Ranch, which are strongly Republican, and to the north, Brighton and part of Thornton, which are part of decidedly blue Adams County. Aurora accounts for about 44 percent of the district’s roughly 815,000 people.

One of Crow’s main jabs is to paint Coffman as being in lockstep with Trump and out of touch with the people of the district.

“Talk is cheap,” Crow said. “People want someone more than who’s going to show up for the photo op.”

It’s a charge the congressman’s campaign vehemently denies.

Whether that point resonates — and to what extent voters’ feelings about Trump can stoke a “blue wave” — may be part of the puzzle of predicting victory in this nationally watched district.

As goes CD6 ...

Which way the district leans will have implications that ring out far beyond Colorado, one veteran pundit said.

“If Coffman is defeated, it will definitely mean that the Democrats are going to take the U.S. House,” said Dick Wadhams, political strategist and former chair of the Colorado Republican Party. “If he survives, it means Republicans have a fighting chance to keep the House.”

In pushing a candidate who has never run for public office before, Democrats are playing to a broader strategy, Masket said. Crow, a former Army Ranger, served in Afghanistan and Iraq.

“They’ve clearly decided if they’re going to appeal to moderates in this district, they should try someone different,” Masket said. “The idea of someone outside of politics with a military background, that seems to be a formula Democrats have been drawing on a lot this year” across the country.

The past two Democrats who ran against Coffman were Andrew Romanoff in 2014 and Morgan Carroll in 2016, both of whom were established politicians after having served in the state Legislature. Romanoff served as state House speaker and Carroll as state Senate president.

Why such a toss-up?

In what’s often referred to as a “purple state,” the district has attracted national attention.

The Cook Political Report, a prominent, nonpartisan newsletter that analyzes elections, lists the district as one of 30 toss-ups in the country — and the only one in Colorado.

But don’t count Coffman out, pundits say. In a district where President Barack Obama won by 5 points in 2012, and Hillary Clinton beat Trump by 9 points, Coffman still won his races in both elections — in 2016, by 8 points. Many voted for Clinton while also voting for Coffman, Wadhams said.

The 6th District once comprised only a portion of Aurora and was mainly made up of GOP strongholds, encompassing almost the entire south metro area, including Castle Rock on the south end and Elbert County to the east. But after a redrawing of the lines in 2011, the district includes Aurora and stretches north all the way to parts of Adams County. Gone from the district are Elbert County and Douglas County, except for Highlands Ranch.

Coffman didn’t wait to get with the times.

“He’s got a sort of flexibility to him,” Masket said. “He got elected to a conservative district that changed its stripes considerably after redistricting.”

Coffman has been aggressive in reaching out to minority communities in the district, Masket added.

As Eric Sondermann, a Colorado political analyst, put it: “Whether you’re talking Ethiopian or Russian Jewish (communities), he does not show up once every election cycle — he shows up repeatedly. He went out and taught himself Spanish.”

That repositioning included adjusting his politics, Sondermann added.

“It’s the whole shebang: his voting record” included, Sondermann said.

Coffman picks “a number of symbolic moments” to distance himself from Republicans, or Trump specifically, Masket said, notably on the recent policy of separating families on a large scale at the U.S.-Mexico border, which drew a sharp rebuke from Coffman. He’s taken a different tone on immigration since the district changed, Wadhams said.

How competitive?

Pundits view Coffman as more vulnerable than in past years, but not dead in the water.

“My thought is, it’s like I’m from Missouri: I’m tired of Democrats telling me they’re going to win it,” Sondermann said. “It’s time to start showing me.”

But 2018 serves up the toughest backdrop Coffman has faced, given backlash against Trump, Sondermann said. As seen in Colorado’s primary race for governor in June, it seems increasingly that local races are focused on national issues, Masket said.

“A lot of this vote is going to be determined simply by how people feel about the president, about national politics,” Masket said.

Despite Colorado’s tilt as a “light-blue state in a deep-blue year,” as Sondermann put it, Wadhams would bet on Coffman to win because of his entrenchment in diverse communities.

If he lost, “it would be less about Coffman and more about a national blue wave,” Wadhams said.

He added: “What we didn’t have two years ago is a Republican president whose approval ratings are upside-down in Colorado.”

On the issues

Where Coffman has adjusted, Crow, a lawyer who spoke at the 2012 Democratic National Convention, seeks to repaint him as a hardline conservative tied closely to Trump, rather than his constituents.

“There’s a very big difference between the Mike Coffman they see … and the Coffman that goes to D.C. and votes with Donald Trump 96 percent” of the time, Crow said. That statistic comes from analysis by FiveThirtyEight, a prominent data-based political outlet, which says Coffman has voted in line with Trump that often since January 2017.

Coffman’s campaign said the statistic is misleading because it includes routine matters, like approving Defense Department funding. FiveThirtyEight’s tracker does include more salient votes, like one to penalize states and localities that have so-called “sanctuary” immigration laws, for which Coffman voted.

Tyler Sandberg, Coffman’s campaign manager, said Coffman has broken with Trump on issues like health care and sanctioning Russia.

Both national issues, like immigration and gun control, and local issues like housing costs will likely play a role in the race, Wadhams said.

Crow wants to cast it as a test of leadership and what he says is Coffman’s “broken promise” to stand up to Trump — a stance Coffman took in a 2016 ad.

“In the Army, I served with folks from every race, every religion” and urban and rural areas, Crow said. “It didn’t matter where we came from — we focused on the mission and we got it done.” He said he could accomplish goals better than a “career politician.”

Coffman said he wasn’t sure what issue would arise as most important in the race because Crow’s campaign has been about “linking me to President Trump.”

“It’s more about politics for him,” Coffman said.

If Coffman survives this test, it may be the last time Democrats make a strong push in the district, Sondermann said.

“If the Democrats are ever going get him, this is the year,” Sondermann said, “but we’ve heard that from the Democrats before.”