An analysis of tens of thousands of nightly Gallup tracking-poll interviews shows that the Republican primary electorate that will choose the party’s 2012 presidential nominee may look very much like the GOP’s voter base in 2008—with some potentially important changes at the margin. In this cycle, the Gallup trends suggest, the primaries could see an increase in both the youngest and oldest participants and a rise in the share of conservative voters.

To preview the potential GOP electorate, Gallup analyzed for National Journal the characteristics of adults who identified as Republicans or Republican-leaning independents in the nightly tracking polls it conducted from January through March 2008, during the height of the nomination struggle that year. Then it compared those findings against the results from its nightly interviews from June through August 2011, the most recent period for which such data are available.

Because the nightly surveys interview so many people (more than 32,000 Republicans and leaners in the first period and more than 36,000 in the more recent three months), the analysis has an extraordinarily low margin of error—only 1 percentage point, according to Gallup.

In most respects, the analysis underscored the durability of the attributes that define the Republican electorate. “We are not seeing a lot of major changes in the composition of people who identify as Republicans,” said Gallup Poll Editor in Chief Frank Newport. “And they remain highly different than the population [overall].”

As in 2008, the Republican coalition today is tilted toward men. Four years ago, men constituted 54 percent of self-identified Republicans and women made up 46 percent. Now the breakdown is 53 percent and 47 percent.

The GOP coalition also remains preponderantly white. Whites constituted exactly 87 percent of Republican supporters in winter 2008; now it’s 86.7 percent. African-Americans have increased as a share of GOP supporters only from 2 percent to 2.7 percent; Hispanics’ representation rose from 6.6 percent to 7.2 percent.

Republican supporters are also somewhat older than the population overall, and that imbalance may tilt even further in 2012. Since 2008, voters younger than 30 increased as a proportion of GOP supporters from 16 percent to 18 percent—a change in line with their increase among the population as a whole. But adults over 50 increased faster as a share of the Republican coalition than they did in the general population. Today, adults over 50 constitute more than 47 percent of Republicans, compared with 44 percent of all Americans. That change reflects the growing Republican strength among white seniors.

The Gallup analysis also suggests that in 2012 the GOP electorate may tilt slightly further to the right than it did in 2008. Back then, 65 percent of GOP supporters identified as conservatives; that number has increased to 68 percent. The share who identify as moderates has declined from 29 percent to 26 percent.

One last change is worth noting: The numbers show a big increase in the percentage of Republicans earning less than $7,500 per month. But those numbers comparably increased for the entire population as well and may reflect a change in Gallup polling techniques, Newport notes.

The Gallup numbers identify Republican supporters; an ABC News cumulative analysis of all the exit polls conducted during the 2008 GOP primaries suggests that Republican primary voters can present a slightly different profile. On most dimensions—including gender, race, and ideology—the primary electorate closely tracked the Gallup findings about GOP supporters. The one exception: Seniors in 2008 represented a slightly larger share of voters than the Gallup numbers would have predicted. If that pattern holds, the 2012 race could have an even more prominent touch of gray than the latest findings suggest. 

Scott Bland contributed

This article appears in the Oct. 29, 2011, edition of National Journal.

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