Last week, pop star Taylor Swift made waves by breaking her stance of political neutrality, and backing Democratic congressional candidates in her home state of Tennessee.

The effect of Swift's surprise endorsement, which was made via an Instagram post, were felt right away, as thousands of people between the ages of 18 and 29 registered to vote, according to Vote.org. However, it remains to be seen whether these new voters will actually turn out for Swift's chosen candidates on Election Day.

Some political observers have their doubts, and history is littered with celebrity political endorsements — overwhelmingly in favor of Democratic candidates — that failed to translate into actual votes. Meanwhile, the latest polling data show Republican Rep. Marsha Blackburn with a sizable lead over Democratic challenger Phil Bredesen in the race for retiring Republican Sen. Bob Corker's seat. Swift urged her followers to back Bredesen, a former governor, in the race.

Yet veteran Democratic strategist Joe Trippi, who worked on the 2004 presidential campaign of Howard Dean, the 2010 campaign of California Gov. Jerry Brown and most recently the successful Senate bid of Alabama's Doug Jones, characterized celebrity endorsements as generating awareness and interest about an election, instead of mobilizing voters.

"It's not so much about changing minds as getting people who aren't paying attention," Trippi told CNBC. "When Charles Barkley came out for Doug Jones in the final weeks of the Alabama special election, we noticed that younger voters weren't paying much attention to the race, but the polling was for us," he said. "Charles Barkley really grabbed some of the spotlight with young voters."

Trippi added that getting the attention of otherwise disengaged voters helped put Jones over the top, in a race where the margin of victory was razor-thin.

"Doug Jones won Alabama by 23,000 votes," he said. "So it can make a difference, not because of changing minds but because you're getting the attention and focus of groups that aren't big turnout demographics."