Andrew Romanoff, right, Democratic candidate for Colorado's 6th Congressional District, takes a tour of Cinema Latino with, from left, co-owner Roberto Sanchez, Rep. Xavier Becerra, D-Calif., co-owners Cesar Sanchez and Louis Sullivan Olmos, in Aurora, Colo., August 26, 2014. Tom Williams / CQ-Roll Call / Getty Images

Republican Rep. Mike Coffman practices his Spanish daily.

On Thursday, he’ll use it in a Univision-sponsored debate conducted entirely in Spanish against Democratic opponent, former state House Speaker Andrew Romanoff.

But it’s possible that by then, five days before Election Day, many of the 6th Congressional District constituents will have already voted in Colorado’s first all-mail general election.

Colorado’s 6th CD race is one of the hottest in the country, and it’s being fought in Spanish-language media, at Asian-American forums and in an African-American community that features many first-generation citizens. Combine that with the convenience of all-mail voting, and you can see why Real Clear Politics rates the contest a tossup.

The district is 20 percent Hispanic, nearly 9 percent African-American and nearly 6 percent Asian, according to Census data.

That’s a significant change for Coffman, originally elected in 2008 to succeed anti-immigration U.S. Rep. Tom Tancredo in what was then a safe Republican district. Redistricting in 2011 changed that makeup, and in 2014, the diverse voter base is set to make a difference.

“The real competition for these Latino votes has become more relevant this time around,” said Abraham Morales, senior associate for Hispanic insights at SE2, a Denver consulting firm.

That’s evident in Spanish-language media, where Romanoff does a weekly radio interview in Spanish and a Denver Telemundo station is truth-testing TV ads.

“One of their findings was that TV ads are as deceiving in Spanish as they are in English,” Morales said.

Coffman is also a frequent guest on Spanish-language media, Morales said.

But the candidates aren’t just reaching out to Latino voters, said Peter Lee, a health-insurance broker and past co-chairman of the Aurora Asian/Pacific Community Partnership.

“There’s more visibility from the parties, the Republican parties and the Democratic parties are more engaged with the Asian community this time around compared to the last 10 years,” Lee said. “This is one of the tightest races in the nation and Asian voters could really make a difference.”

Morales noted that Arapahoe and Adams counties, where most of the Asians, Latinos and African-Americans live, have high numbers of unaffiliated voters. That means candidates must reach out to these groups on issues, Lee said.

“The economy is a big issue. Immigration is also a big issue as well,” Lee said. “We tend to vote on the issues, rather than on the party line.”

That’s where mail-in ballots come in. For the first time in a general election, all registered Colorado voters are receiving ballots by mail, which they may return through the mail or in person. There are also early voting centers and in-person voting on Election Day for those who prefer casting ballots in person.

A study of Denver’s all-mail ballot elections between 2004 and 2007 “found fairly sizable turnout effects in primarily Latino and black precincts,” said Peter Miller, a post-doctoral fellow at the University of Pennsylvania who studies turnout and early voting. For instance, minority voter turnout increased between 18 percent and 20 percent in the Denver study, Miller said, in part because of the convenience.

“Part of the conventional wisdom is that if you make voting easier to do, more people will do it,” Miller said. “All-mail balloting is one of the ways in which you can reduce the opportunity costs of voting.”

Lee agreed, noting that the 6th CD’s Asian community includes many self-employed entrepreneurs who are often working during traditional polling hours. And they’re often not accustomed to the bustle and bureaucracy of in-person voting precincts.

“Asians are a little intimidated in going to polling places,” Lee said. “The mail-in ballot can be a much better solution. It’s a way to make our voices heard.”