Despite pressure from party leaders, Mayor Cory A. Booker of Newark will not challenge Gov. Chris Christie for re-election next year in New Jersey, deciding instead to focus on making a bid for a Senate seat in two years.

“Let there be no doubt, I will complete my full second term as mayor,” Mr. Booker wrote on his Web site. “As for my political future, I will explore the possibility of running for the United States Senate in 2014.”

Mr. Booker, seen by many as a rising political star, was considered by Democrats to be their best hope to unseat Mr. Christie, a Republican. Mr. Christie’s popularity, however, has surged since Hurricane Sandy, and Mr. Booker, who has faced growing criticism in his second term that he has been more focused on publicity than the mundane work of managing, most likely would have faced an uphill battle, according to the most recent polls.

The decision to skip the race for governor, which Mr. Booker shared with party leaders before his announcement, clears the path for someone else to challenge Mr. Christie. A number of Democrats have expressed interest in taking on one of the nation’s most prominent and provocative political figures.