Political Geography: Colorado - NYTimes.com Characterizing an electorate for a caucus is much trickier than doing so for a primary. That's a reason there have been very few polls previewing Tuesday's contests - it's difficult for pollsters to model the likely turnout. Only about 70,000 Colorado Republicans participated in the state's 2008 presidential caucus, so the peculiarities of any election can markedly change the profile of those who show up. There are, however, some notable constituencies that make up the Colorado Republican electorate. To get a sense of who they are and where they live, FiveThirtyEight looked to Seth Masket, an associate professor of political science at the University of Denver, and Kyle Saunders, an associate professor of political science at Colorado State University. The Republican Party's base of support in Colorado is to the south and east of Denver. First, there are the Denver suburbs, where almost 40 percent of the state's Republicans live, according to voter registration statistics compiled by Colorado's Secretary of State's office. In many ways, they are typical suburban Republicans: establishment friendly, fiscally focused and perhaps a little more moderate on social issues than Colorado Republicans farther to the south. Mitt Romney won these counties easily in 2008 (Adams, Arapahoe, Douglas and Jefferson), but he won the entire state by a wide margin, so that doesn't tell us much. Moving farther south from Denver, you approach El Paso County, where Colorado Springs is located. This is the heartland of Colorado's evangelical community. Focus on the Family is based here. In 2008, among the state's most heavily populated counties, Mike Huckabee did best in El Paso County and, to the south, Pueblo County. Rick Santorum, who like Mr. Huckabee appeals to evangelicals and social conservatives, should do well there, too. El Paso County contains about 15 percent of Colorado's registered Republicans, the largest share of any county. In addition to a heavy evangelical presence, the area includes significant military installations, like Fort Carson and Peterson Air Force Base. The farther you travel away from Denver, the more rural Colorado becomes and the higher the share of farmers and ranchers. The Western Slope, essentially everything west of the Rocky Mountains, and the Eastern Plains, roughly speaking, all the counties bordering Kansas, will contribute just a tiny share of caucus-goers on Tuesday. But Mesa County, home to Grand Junction, does have 4 percent of the state's Republican Party. A couple of last points to keep in mind: First, you hear a lot about Colorado's burgeoning Hispanic community, but Hispanics in the state have skewed decidedly Democratic and probably will not make up a significant share of Tuesday's caucus-goers. Second, the Tea Party has been extremely active in Colorado. In the state's 2010 Senate race, the establishment-backed Republican, Jane Norton, a former lieutenant governor, was bested in the party's primary by Ken Buck, a district attorney from Weld County, who had the support of Tea Party activists. Mr. Romney essentially swept the state in 2008, but at that time, he was perceived as more conservative than the other major candidates. Mr. Romney has led the few polls that have been conducted in Colorado, but he is playing "the moderate" in this election and has struggled with the most conservative wing of the Republican electorate.