NEW YORK — Donald Trump pleaded not guilty Tuesday in front of a New York state judge to 34 felony charges of falsifying business records as he became the first former U.S. president in history to be arrested, in a prosecution hotly challenged by Mr. Trump and his attorneys as a partisan investigation. Manhattan District Attorney Alvin Bragg, a Democrat who campaigned on a promise to indict Mr. Trump, accused the former president of improperly influencing the 2016 election by orchestrating the payments to quash negative news stories about him and then falsifying his corporate business records about the reasons for those payments.