Poll: Dems' advantage in party affiliation increased last month

The current data show a similar pattern, with party affiliation moving toward the president’s party as he has gained popularity. However, the magnitude of the change reflects the more modest increase in Obama’s approval rating.

Gallup measured a six-point bounce in Obama’s approval rating in the days immediately after Osama bin Laden’s death, which is typical in size for a presidential rally.

Had the rally been larger, party affiliation likely would have shifted even more in a Democratic direction. For example, between the third and fourth quarters of 2001, spanning the 9/11 terrorist attacks, the party affiliation gap shifted six points toward the Republicans as George W. Bush received record-high approval ratings.