PRINCETON, NJ -- The percentage of Americans identifying themselves as Republicans has increased from 26% immediately before last week's Republican National Convention began to 30% immediately after it. That increase, combined with a slight 2-point drop in Democratic identification from 37% to 35%, has reduced the Democrats' formidable advantage in national party identification from 11 points to 5.
Democrats have held a large advantage on party identification for much of 2007 and 2008. But the GOP convention -- and the exposure it gave to John McCain and Sarah Palin as the Republican ticket -- has encouraged a greater number of Americans to identify as Republicans, thus narrowing the Democratic advantage for the moment.
Republicans saw an even larger increase in "leaned" party identification, which is computed by adding the percentage of Americans who initially identify themselves as independents but then say they "lean" to a party to the percentage who identify with that party. Before the GOP convention, 39% of Americans said they identified with or leaned to the Republican Party, but that number has increased to 47%. Forty-eight percent now identify with or lean to the Democratic Party, down from 53% prior to the GOP convention.
These results are based on the Sept. 5-7 USA Today/Gallup poll, but Gallup observed similar trends in its daily tracking survey.
Such short-term shifts in party affiliation are a regular occurrence after a party's convention -- Gallup has measured an increase in the percentage of Americans identifying with a party after its convention since 1992, averaging 4 percentage points.
The increases have been slightly larger, averaging 5 points, when one looks at changes in leaned party identification. This year's 8-point surge in GOP identification and leaning matches the Democrats' high from 2000. Each party has enjoyed an increase in leaned party identification after its convention, with the exception of this year's Democratic convention. That may reflect the already-high percentage of Americans identifying with or leaning to the Democratic Party this year before its convention began.
Republican Party's Image Improves
Another common measure of a party's standing is the public's favorable rating of that party. Currently, 47% of Americans say they have a favorable view of the Republican Party, an increase from 39% before the convention, and the best rating for the GOP since early 2005.
Even in the afterglow of the Republican convention, the Democratic Party is still rated more positively than the Republican Party, with 51% of Americans saying they have a favorable view of the Democrats. That is down slightly from before the Republican convention (54%). A majority of Americans have had a favorable view of the Democratic Party since the summer of 2006.
As is the case for party identification, favorable ratings of the parties usually increase after a party's convention. The average increase in favorable ratings since 1996 has been 4 points, with the Republicans' 8-point surge this year the largest (perhaps because the image was so poor going into the convention). Again, the Democratic Party's highly positive image did not improve after its convention this year.
Implications
The conventions present the parties with an important opportunity to speak directly to their supporters and the nation at large, and to convey their messages in a positive light. Thus, it is not surprising to see each party's public image improving after its convention.
But are those increases temporary, or do they have some staying power? In general, it appears that the increases are short-lived and fade as the enthusiasm from the convention subsides.
Since 1996, the percentage of Americans who identify with or lean to a party has dropped in the poll after that year's post-convention poll for each party. So to the extent history is a guide, Gallup's next survey would likely show a slight drop in the percentage of Americans identifying with or leaning to the Republican Party.
And while Gallup does not ask the party favorable question as regularly as it does party affiliation, the post-convention poll for a party has often marked the high point in favorable ratings for that party each presidential election year.
Thus, while the Republicans have cut into the Democratic advantage in party identification, it is likely that this year's election will still be contested in a political environment that is more favorable to the Democratic Party than the Republican Party.
Survey Methods
Results are based on telephone interviews with 1,022 national adults, aged 18 and older, conducted Sept. 5-7, 2008. For results based on the total sample of national adults, one can say with 95% confidence that the maximum margin of sampling error is ±3 percentage points.
Interviews are conducted with respondents on land-line telephones (for respondents with a land-line telephone) and cellular phones (for respondents who are cell-phone only).
In addition to sampling error, question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of public opinion polls.
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