For the first time in 16 years, the election for Suffolk County district attorney won’t involve Thomas Spota — and in his absence, more than a dozen potential candidates are jockeying for prized major and minor party endorsements.

Spota, first elected as a Democrat in 2001, received the backing of Democrats, Republicans, Conservatives and the Independence Party in all three of his re-elections, ensuring that his name was always the only one on the November ballot.

That political dominance made challenges rare. Attorney Ray Perini was one of the few to try, losing a 2013 GOP primary bid by a wide margin, after Spota had won a lawsuit to exempt the district attorney’s office from Suffolk’s 12-year term-limit law.

But this year, as it became less likely that Spota would seek a fifth four-year term, potential candidates from various corners of the law enforcement community began testing the political waters with increased frequency.

Most prominent among them is Suffolk Police Commissioner Timothy Sini, a former federal prosecutor and ally of County Executive Steve Bellone who initially told county lawmakers he wouldn’t run.

Other potential Democratic candidates include David Calone, a venture capitalist who also worked as a federal prosecutor; William Wexler, a defense attorney and former county prosecutor who shares offices with Suffolk Democratic chairman Richard Schaffer; Tad Scharfenberg, a defense attorney and former county prosecutor who ran for district attorney in 1997; James Chalifoux, deputy bureau chief of the district attorney’s major crimes bureau; Maureen McCormick, a top Nassau prosecutor who lives in Huntington; and Laura Ahearn, executive director of Parents for Megan’s Law, an advocacy group for victims of sexual assault.

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Among Republicans and Conservatives, Perini, a former district attorney’s narcotics bureau chief, has announced his intention to run. Other potential Republican or Conservative candidates are William Ferris, a Navy veteran and former prosecutor; Robert Biancavilla, top homicide prosecutor in Spota’s office; John Halverson, a private practice attorney and former county prosecutor; Edward Friedland, district executive of the U.S. District Court in Manhattan; Andrew Crecca, a state Supreme Court justice and former county legislator; and Patrick O’Connell, a former prosecutor who is in private law practice with Suffolk County Conservative chairman Frank Tinari.

The county’s party chairmen have yet to announce their favored candidates.

Michael Dawidziak, a Bohemia political consultant who works largely with Republicans, said: “It becomes a democracy in November. Now it’s in the parties’ purview.”

With Suffolk’s history of cross-endorsements, he added that voters shouldn’t assume that it will be an open field.