(Reuters) -- Twitter Inc on Friday dropped a lawsuit it filed the previous day against the U.S. Homeland Security Department, saying the government had withdrawn a summons for records about who was behind an account critical of President Donald Trump. A lawyer for the social media company, Mark Flanagan, wrote in court papers that a U.S. Justice Department lawyer told Twitter about the withdrawal of the summons on Friday and that the demand "no longer has any force or effect." It was not immediately clear why the government had withdrawn the summons, or whether it had closed an investigation it said it was conducting. The Justice Department, which defends federal agencies in court, declined to comment. The Homeland Security Department, which issued the summons, had no immediate comment. The abrupt end to the dispute may indicate that Justice Department lawyers did not like their chances of succeeding in a fight about speech rights, said Jamie Lee Williams, a staff attorney a