Gallup editors review the key indicators that are likely to determine the outcome of the U.S. presidential election, putting the current data into historical context.

Herman Cain and Rick Perry generate the strongest favorable images among Republicans familiar with them, and have separated themselves from the remainder of announced GOP candidates as Michele Bachmann, Mitt Romney, and Ron Paul have tied or set ...

Mitt Romney has moved ahead of Newt Gingrich in national Republican voters' preferences for the 2012 GOP nomination, 31% to 26%, according to Gallup Daily tracking from Jan. 27-31.

Congress' job approval rating has improved to 25%, the highest since early June.

Mitt Romney has climbed to a commanding 23-point lead over his nearest Republican competitor, with the support of 37% of Republicans nationwide. Rick Santorum and Newt Gingrich each have 14%, and Ron Paul has 12%.

U.S. population growth has slowed significantly, the result primarily of significant trends related to fertility and immigration.

Barack Obama is closely matched against four leading GOP candidates in prospective presidential election trial heats. Mitt Romney edges Obama by two percentage points among registered voters. Rick Perry and Obama are tied, but Obama has a slight ...

No third-party candidate gets more than 3% of the vote in the U.S. presidential race, as the vast majority of U.S. voters say they would vote for either Barack Obama or Mitt Romney if the election were held today.

The Republican presidential race is now a 32% to 30% statistical tie between Mitt Romney and Rick Santorum, in Gallup interviewing conducted wholly after Santorum's victories in the Feb. 7 nominating contests.

As he turns to the general election campaign, Mitt Romney faces the challenge of generating enthusiasm and, hence, turnout among Midwestern, young, highly religious, and conservative Republicans -- groups among whom he has struggled.