WASHINGTON • The chairman and the Joint Chiefs of Staff unanimously supported the Obama administration’s exchange of five Taliban leaders for an Army sergeant held prisoner in Afghanistan for five years. In letters to the head of the Senate Armed Services Committee, the nation’s seven top military leaders insisted the United States has a sacred commitment to men and women who serve that it will never leave anyone behind on the battlefield. Army Gen. Martin Dempsey, the chairman of the Joint Chiefs, said the swap in May was “likely our last, best opportunity” to free Sgt. Bowe Bergdahl. The administration has come under harsh criticism from many in Congress, especially Republicans, who have said Bergdahl was a deserter and the United States gave up too much for his freedom. Several lawmakers have cited intelligence suggesting the high-level Taliban officials could return to the Afghanistan battlefield. Five senior Taliban were released from detention at Guantanamo Bay, Cuba, in exchange for Bergdahl, who had disappeared from his post in Paktika province in eastern Afghanistan on June 30, 2009. The five Taliban are to remain in Qatar for a year. Adm. James Winnefeld wrote in his letter that while the five are hard-core Taliban, they never posed a direct threat to the U.S. homeland or American interests outside Afghanistan. “I do not consider any of them to be ’game changers’ in being able to substantially alter the military situation or otherwise provide considerable benefit to the Taliban campaign,” Winnefeld wrote. Army Gen. Ray Odierno said the five Taliban had been held at Guantanamo for more than a decade and the fight has changed since then, reducing their relevancy. Several members of the Joint Chiefs said they did not know the specific details of the swap in advance. Lawmakers were furious that President Barack Obama failed to notify Congress 30 days in advance, as required by law. Sen. Carl L, D-Mich., chairman of the Armed Services panel, requested the letters and released them on Thursday. “Each of these military leaders emphasized a simple principle — America does not leave its troops behind,” L said in a statement. “The unanimous support of the Joint Chiefs for securing Sergeant Bergdahl’s release is a powerful statement on the importance of that commitment. I give great weight to their views, and I believe it’s important for the American people to hear them.“ Bergdahl returned to the United States on June 13 and has been receiving care at a Texas military base as part of his “reintegration process” into society.