Before, during, and after Election Day, Trump and numerous Republicans attempted to subvert the election and overturn the results, falsely alleging widespread voter fraud and trying to influence the vote counting process in swing states. Attorney General William Barr and officials in each of the 50 states found no evidence of widespread fraud or irregularities in the election. Federal agencies overseeing election security said it was the most secure in American history. The Trump campaign and its allies, including Republican members of Congress, continued to engage in numerous attempts to overturn the results of the election by filing 63 lawsuits in several states (all of which were withdrawn or dismissed), spreading conspiracy theories alleging fraud, pressuring Republican state election officials and legislators to change results, pressuring the Department of Justice to declare the election "corrupt" and intervene, objecting to the Electoral College certification in Congress, and refusing to cooperate with the presidential transition of Joe Biden. This culminated in a mob of Trump supporters attacking the United States Capitol on January 6, 2021, and Trump being impeached for incitement of insurrection. Trump said repeatedly that he would never concede the election. However, on January 7, 2021, one day after the violent Capitol attack and two months after Biden's victory was declared, Trump acknowledged the incoming administration without mentioning Biden's name in a video posted to Twitter.