Former Vice President Mike Pence has been subpoenaed by the special counsel investigating former President Donald J. Trump's efforts to cling to his office after he lost his bid for re-election, a person familiar with the matter said on Thursday. The move by the Justice Department sets up a likely clash over executive privilege, which Mr. Trump has previously used to try to slow, delay and block testimony from former administration officials in various investigations into his conduct. The subpoena is the latest sign that the special counsel, John H. Durham, is examining the events of the last weeks of the Trump administration, when the president and his allies sought to overturn the results of the election through false claims of widespread fraud. It is unclear what information the special counsel is seeking from Mr. Pence. The subpoena could also be an indication that the special counsel is looking into whether Mr. Trump and his allies sought to use the power of the presidency to pressure state and federal officials to overturn the election results. The subpoena is the latest move in a long-running investigation by Mr. Durham, who was appointed by Attorney General William P. Barr in May 2019 to investigate the origins of the Russia investigation. Mr. Pence has not publicly commented on the subpoena, and it is unclear if he will comply or challenge it. If he does challenge it, the matter could end up in court. The investigation is the latest in a series of controversies involving Mr. Trump and his allies, who have been accused of abusing the power of the presidency and attempting to undermine the integrity of the election. It remains to be seen what the outcome of the investigation will be, but it is clear that the special counsel is taking a closer look at the events of the last weeks of the Trump administration.