AURORA, Colo.—On Thursday evening, Republican Rep. Mike Coffman and his Democratic opponent in Colorado's 6th Congressional District, Andrew Romanoff, will debate in Spanish—a language Coffman didn't speak at this time in his last race.

It will be the first-ever Spanish-language congressional debate in Colorado, and it may be the first time ever that two Anglo House candidates have debated in Spanish anywhere. And the Republican has been working up to this moment for months.

After being redistricted from a conservative seat into more diverse territory in 2011 and narrowly escaping defeat in the 2012 elections, Coffman dedicated himself to adapting to the newly drawn battleground district, which included learning a new language in his late 50s. Through lessons over the phone on weeknights and in person on Saturdays and Sundays for the past year, plus immersion with some of his 150,000 or so Hispanic constituents, Coffman has gained enough proficiency to take the stage Thursday.

Democrats and some immigration activists take issue with the attention Coffman has received for learning the language, arguing that it masks a political agenda hostile to Hispanics. "I don't think his record sounds any better in Spanish," Romanoff said in an interview. (Romanoff taught in Latin America in the '90s and is fluent in Spanish.) 

But you can't argue with the effort that goes into learning a language well enough to debate in it. Romanoff has arguably been the most impressive and hard-working Democratic candidate in America in 2014—and Coffman has met the challenge. Together, the two campaigners have been running a grueling two-year marathon in a district like no other in the country, leaving their young staffers equal parts impressed and sprinting to keep up.

There are more than 130 different expat communities in Aurora, the district's population center. About one-fifth of the residents are Hispanic, but there are tight-knit groups of first- and second-generation citizens from Korea, China, a number of African countries, and many others on which both candidates have lavished attention over the past two years, ahead of an election that could be decided by a few thousand votes.

On a recent Saturday, tracking down Romanoff required a trip to Ugandan Independence Day festivities at a local community center. The Democrat spoke to the crowd of a couple hundred people after dinner, but he arrived early in the evening and stayed late, shaking hands, answering questions on subjects from student-loan rates to Ebola, taking pictures with young kids, and moving to the front of the room for a better look at the children's group performing a musical set.

When it was his turn to speak, a MC told the group that Romanoff was there to speak to them "again," and the candidate opened his remarks with a few words in Swahili, drawing a whoop from the crowd, before talking briefly about his economic plan and immigration reform and asking for their support. "I'm the son and the grandson of immigrants," Romanoff said in his speech. "And I'm glad we're here. Because I think we're richer in every way, not just as a family but as a country, we're better off because we have welcomed so many people from so many different lands, including Uganda."

The issue of immigration reform highlights the work the 6th District demands of its representatives. Coffman's evolution on immigration—from anti-"amnesty" supporter of Tom Tancredo (who Coffman once called a "hero") to current supporter of legal status for undocumented immigrants and citizenship for their children—has gotten a lot of attention nationally and in Colorado, and the comprehensive immigration-reform legislation that passed the Senate but died in the GOP-controlled House without Coffman's support is a main point of Romanoff's campaign. But there's also a big constituent-services angle on immigration that Coffman has attacked vigorously in his first term in the new district.

E-2 visas are a particularly big concern for the Korean community, Coffman campaign manager Tyler Sandberg said, while "the Chinese community is more concerned with E-5 visas." Coffman's office has worked to connect both communities with federal resources and worked on a bill on E-2 visas. The Republican has been spending his weekends visiting different constituent groups' neighborhoods and events—test-driving his Spanish skills and talking through his new position on immigration in some of them. Elsewhere in the country, "Republicans haven't learned to put that time in, to reach people at nonpolitical events," said Sandberg, who thinks Coffman's efforts should be a national model for the GOP. "As soon as you've had that personal meeting, good luck attacking him on TV."

Both candidates have excelled in another, quantifiable area of political preparedness. Romanoff raised more money (around $5 million) than any other House challenger in the country in 2013 and 2014, a particularly impressive feat considering that he didn't accept funds from political action committees. And Coffman, who was not a particularly good fundraiser in his first few years in Congress, kept close behind his opponent. Given how gobs of outside money flock to the few competitive House races these days, that cash has proven necessary for both candidates to get their own messages out this fall.

On the ground, Democrats have been executing a massive field program in Colorado to try to get unlikely voters to cast ballots this fall, and Romanoff has been personally knocking on doors for months as part of that effort. But the GOP has a smaller cohort of "drop-off" voters too, and Coffman has executed a labor-intensive strategy to get their help in a district President Obama carried twice. Every Republican in the district who cast a ballot in 2012 but not in 2010 received a handwritten letter from Coffman asking for their support this year, Sandberg said, in addition to his door-to-door efforts.

Coffman is "exhausting to keep up with," Sandberg says. Democratic Sen. Michael Bennet fought a bitter primary against Romanoff in 2010, but at a recent get-out-the-vote event, the senator praised his one-time adversary's industriousness. "Please welcome the hardest-working person in show business, Andrew Romanoff!" Bennet shouted at the rally.

Democrats and Republicans intersect on few issues at this time of year, but both sides in the 6th District definitely agree on one thing: Both candidates have been campaigning like madmen.

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