Frank Lautenberg has been elected five times in New Jersey for a United States Senate seat, but according to a new poll, a sixth victory wouldn't be an easy accomplishment. The 88-year-old has not yet announced if he'd seek another term.

The survey from Fairleigh Dickinson University's PublicMind found the incumbent falls short in a matchup against the Democrat who just threw his hat into the ring for next year's race, Newark Mayor Cory Booker. Among registered Democrats in New Jersey, 42 percent would prefer Booker over Lautenberg, compared with 20 percent who prefer Lautenberg over Booker.

U.S. Senator Frank Lautenberg, D-NJ (Mark Wilson, Getty Images)

In addition, the mayor's favorable rating eclipsed that of Senator Lautenberg by a sizable margin (66 to 45 percent).

"These numbers suggest that some difficult days may lie ahead for the incumbent senator should he seek reelection," said Krista Jenkins, director of PublicMind and professor of political science at Fairleigh Dickinson University.

The poll also showed almost even name recognition for the two potential contenders. Three-fourths of registered voters expressed familiarity with Booker; Lautenberg garnered notability among 83 percent.

"Booker has clearly leveraged his position as mayor of Newark to an admirable degree," added Jenkins.

Booker's popularity with the voters could, perhaps, be attributed to his heavy use of social media. Recently, he took on a "Twitter challenge" to live on food stamps for a week. He has also had high-profile spats with city officials and celebrities through YouTube.

Also, the mayor became a temporary national hero in April 2012 when he rescued an elderly neighbor from a burning building.

This week, Lautenberg called on Vice President Joe Biden and his national task force on gun violence to include the Senator's bills in their recommendations to Congress; Lautenberg's measures would close the gun show loophole, ban high-capacity magazines, and prevent the sale of firearms to known and suspected terrorists.

Newark Mayor Cory Booker (Getty Images)

The FDU survey also asked respondents about the nation's president and the job he's doing.

Garden State voters were decidedly supportive of President Barack Obama's job performance; fifty-seven percent approved of the job he is doing, while only a third gave him disapproving marks.

"Partisan acrimony over the so-called 'fiscal cliff' doesn't appear to have hurt the president in the Garden State," said Jenkins.

The 57 percent approval rating is Obama's highest PublicMind figure in more than three years.

The poll of 700 voters statewide was conducted by telephone from January 2 through January 6. It has a margin of effort of +/- 3.7 percentage points.