Is Colorado still a “purple” state that, in the future, will see voters split their votes between the Democratic and Republican parties? Or, in light of the strong performance by the Democrats in the 2018 general election, is Colorado becoming mainly Democratic – a “blue” state?

To answer these questions, we decided to first look backward over the past half-century of Colorado voting statistics. We studied major statewide elections for U.S. president, U.S. senator, and Colorado governor. Using only Democratic and Republican election results (we excluded third parties), we divided the study into five separate decades – the 1970s, 1980s, 1990s, 2000s, and 2010s.

For each decade we calculated a Statewide Partisan Average (SPA), an average number summing up how the two political parties did against each other over that decade of time.

The SPA metric is something we devised many years ago. Yes, it is a bit wonky, but anyone can do the math with data provided by the Colorado Secretary of State’s Office.

Thus, in the decade of the 1970s, Colorado had a SPA of 51.2 percent Republican. Compared to many other states in the United States, that is a close split. Many other states are strongly Democratic or strongly Republican.

In the 1970s, Richard Nixon won a big victory for the Republicans in Colorado in the 1972 presidential election, but the ensuing Watergate scandal forced Nixon to resign the presidency. The Democrats in Colorado took advantage of this Republican scandal and elected Dick Lamm governor in 1974 and reelected him in 1978. Thus both parties had winning candidates in the 1970s, and the close SPA, 51.2 percent Republican, reflected that.

We go on to the 1980s. It was the most Republican decade in recent Colorado electoral history. The SPA hit 52.4 percent Republican, mainly thanks to Republican Ronald Reagan’s twin victories in the 1980 and 1984 presidential elections in Colorado. Democrats continued to dominate gubernatorial elections, however. Lamm was easily reelected to a third term as governor in 1982 and Roy Romer, also a Democrat, succeeded Lamm in the governor’s office in 1986. Republican presidential victories were mainly counterbalanced by Democratic gubernatorial wins, so the SPA stayed close at 52.4 percent for the GOP.

The 1990s were a comeback for the Democrats, and the decade ended with Colorado having a SPA of 50.6 percent Democratic. Bill Clinton won Colorado for the Democrats in the 1992 presidential election, but Republican Bob Dole narrowly defeated Clinton in the presidential sweepstakes in 1996. Democrat Roy Romer was reelected governor in 1990 and 1994, but Republican Bill Owens won the governor race in a squeaker in 1998. That super close SPA of 50.6 percent Democratic in the 1990s is what put the idea in people’s heads that Colorado was indeed a “purple-ish” state.

But the SPA score became even closer in the decade of the 2000s and ended up at 50.4 percent Republican, the closest the two parties came to an even balance in the 50-year period studied. Republican President George W. Bush carried Colorado handily in the 2000 and 2004 presidential elections, but President Barack Obama did even better for the Democrats in 2008. Republican Bill Owens was reelected governor by a big margin in 2002, but Bill Ritter took the governor’s office back for the Democrats in 2006. Again there is this pattern of both parties winning major statewide offices throughout the decade, thereby explaining that 50.4 percent Republican SPA for the early 2000s.

And now it is on to the present decade of 2010 to 2018. The SPA stands at 52.2 percent Democratic, the best the Democrats have done in any decade from 1970 to 2018. That is almost as good as the Republicans did in their best decade with 52.4 percent Republican in the 1980s. Barack Obama carried Colorado comfortably for the Democrats when he was reelected president in 2012, and Hillary Clinton won Colorado just as comfortably from Donald Trump in 2016. The only Republican win in a statewide election in Colorado in the 2010-2018 decade was Cory Gardner’s election as U.S. senator in 2014. At an SPA of 52.2 percent Democratic, the 2010s have been the Republican Party’s weakest decade in Colorado over the past half century.





1970-1978 51.2 R

1980-1988 52.4 R

1990-1998 50.6 D

2000-2008 50.4 R

2010-2018 52.2 D



SPA=Percentage votes for U.S. President, U.S. senator, and Colorado governor averaged together by decade.

So what can be concluded from this 50-year decade-by-decade study? Over the long haul, it appears Coloradans consistently vote in a narrow range of 52.4 percent Republican to 52.2 percent Democratic. Thus there is no historical evidence Colorado voters ever want to go strongly Democratic or strongly Republican for an extended period of time. For fifty years the statewide vote has stayed close to the 50 percent mark that determines victory and defeat. The result is that Democrats and Republicans both get elected in the state most of the time.

Can the Republicans “come back” from the fact that the Democrats have been on a winning streak in the 2010s and currently enjoy a 52.2 percent Democratic advantage? Well, the Republicans had a slightly better figure of 52.4 percent Republican in the 1980s, and by the end of the 1990s that Republican lead was gone. The Democrats could lose their current advantage the way the Republicans lost theirs in the 1990s.

And then there is this point. The Democrats have won a large number of statewide offices in Colorado recently, but they have won most of them by narrow victory margins in the range of 50 to 52 percent. And in every case, Democratic candidates won only because they were better able to sway a majority of Colorado’s large and growing unaffiliated voters. With things this close in Colorado, and most unaffiliated voters regularly up for grabs, the Republicans will not have to reverse that many votes to start winning again.

The Democrats now control all but one of the major statewide offices that compose the SPA. It is well-known, however, that voters, in Colorado as well as elsewhere, have a tendency every eight years or so to vote for out-of-office party candidates. That could help the Republicans as well, especially when, or if, Republicans can better overcome their ideological divisions. This, going forward, may be a big “if.”

Most pundits are forecasting Colorado as a now a predictably “blue,” or Democratic, state. This may prove to be the case, and demographic changes help to make that case. Further, Governor Polis is off to a good start, and Republican U.S. Senator Cory Gardner is understandably losing sleep over a likely contest against former-Governor John Hickenlooper in 2020. Still, as our close look at the last 50 years suggests, we would not yet “short” Republican chances over the next decade.

Warning: Just as in the stock market, past electoral performance never guarantees future gains. Except, we note, markets have an impressive way of coming back and going up after corrections, and even after recessions and depressions. So “blue-ness” will depend more on performance than on future expectations. That’s the way it has worked in Colorado over the past five decades.

Tom Cronin and Bob Loevy are political scientists at Colorado College.

Load comments