PRINCETON, NJ -- Mitt Romney's standing in the presidential election campaign has not changed materially in the immediate days after his announcement of Wisconsin Rep. Paul Ryan as his vice-presidential running mate. The first four days of Gallup Daily tracking after Romney's announcement show 47% of registered voters saying they would vote for Romney and 45% for Barack Obama if the election were held today. The four days prior showed Romney at 46% and Obama at 45%.

While the initial indication is no increase in Romney's support after naming Ryan, the data suggest the possibility that Romney may get a delayed bounce, as he fared slightly better in Aug. 13-14 Gallup tracking than in Aug. 11-12 tracking.

The lack of an immediate increase for Romney is consistent with Sunday's USA Today/Gallup poll that found a generally tepid reaction to the Ryan pick, especially in comparison to past vice-presidential choices.

Like this year, Gallup also did not find any significant change in voter preferences for the 2008 election after Obama and John McCain each named his running mate. However, in the 1996-2004 campaigns, the vice presidential choice seemed to have a more noticeable impact on voters.

Gallup cannot accurately assess the effect of vice presidential announcements on voter preferences prior to 1996, given the timing of polls and other campaign events in those years. Specifically, in many earlier elections, the vice presidential choice was made during the party's nominating convention, so it is not possible to isolate any change in voter preferences due to the vice presidential choice from changes associated with the party's conventions, which usually produce a bounce for the nominee.

Implications

Although the announcement of Romney's running mate will be one of the more significant events in the 2012 campaign, it has not done much to change voter preferences, at least initially.

Gallup Daily tracking in the coming days may reveal greater movement toward Romney, though the more days that pass after the Ryan announcement, the less likely it is that the movement will be due to choosing Ryan as opposed to other possible factors. The next scheduled major event that will have the potential to affect the race will be the Republican convention, which begins Aug. 27 in Tampa.

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