Arizona by the Numbers – Surging Independent Enrollment

February 27th, 2012



In the years since the Obama election, Independent enrollment has surged 20% in Arizona while Democratic and Republican enrollment are both down. Arizona technically has a “closed” primary—meaning that only registered Republicans are allowed to vote in the GOP race. But the rules allow voters to switch their enrollment up to 2 days before the balloting. In 2008, 18% of those who voted in the GOP primary called themselves Independents. Whether sizable numbers of Independents will make the switch by Tuesday is unknown, but one thing is clear: come November, Arizona Independents will decide the state.

Voter Registration Changes

Arizona Statewide Voter Registration Changes[1]

Year Democrat Republican Independent
2008 1,161,982 1,262,871 988,185
2010 1,121,396 1,230,654 1,116,384
2012 1,090,136 1,229,340 1,204,056
Change 2012-2008 -71,846 -33,531 +215,871
% Change Since 2008 -6.2% -2.7% +21.8%

As illustrated above, Arizona now has more Independent voters than Democrats, and they are closing in on the Republicans, too. Maricopa County is the fastest growing county in the United States, according to the most recent census. While Republican and Democratic registration has declined since 2008, Independent registration has once again increased, paralleling statewide trends.

Maricopa County Voter Registration Changes

Year Democrat Republican Other
2008 624,663 785,078 587,554
2012 587,089 755,528 721,112
Net Change -37,574 -29,550 +133,558
% Change -6% -3.8% +22.7%

2008 GOP Primary

In 2008, with just over half a million ballots cast Sen. McCain won the Republican primary in Arizona with 47% of the vote, followed by Gov. Romney with 35%. Gov. Romney won only 3 counties in Arizona—Navajo (54%), Apache (43%), and Graham (66%)—and Sen. McCain won the rest.

2008 GOP Primary Results

McCain 255,197 47%
Romney 186,838 35%
Huckabee 48,849 9%
Paul 22,692 4%
Total 513,576 95%

Of the GOP primary voters, 18% self-identified as Independent (all voters are technically required to register as a Republican 2 days prior to the primary election) and 68% were from Maricopa County. Sen. McCain won a plurality of Maricopa County. However, as noted above, Maricopa County has seen explosive growth in Independent (technically “unaffiliated”) voter registration. The outsized importance of Maricopa County likely means that whoever wins there, wins the state (much like in 2008).

Maricopa County GOP Results Primary 2008

McCain 167,717 48%
Romney 116,995 33%
Huckabee 28,709 8%
Paul 15,106 4%
Total 328,527

2008 General Election

In 2008, Sen. McCain beat Pres. Obama by nearly 200,000 votes, winning 54% of the vote:

  • Sen. McCain won 1,230,111 votes, or 54%; and,
  • Pres. Obama won 1,034,707 votes, or 46%.

According to the 2008 statewide exit polls, 32% of the electorate was Democrats, 39% was Republicans, and 30% was Independents. The President’s campaign is smart to consider Arizona a toss-up. In 2008, even though McCain won 92% of Republicans, he still needed to win most of his 46% of Independents to secure the state. And with a 20+ point increase in registered Independents since 2008 and declines in both parties’ enrollments, Independents will be even more important this time around.

[1] All voter registration data is from the Office of the Arizona Secretary of State. The 2012 registration counts are accurate as of February 22, 2012. Arizona Secretary of State, “State of Arizona Voter Registration Report,” February 22, 2012, Accessed February 24, 2012. Available at: