Ahead of what could be the largest ever initial public offering, the company painted a nuanced picture: Despite risks, A.I. could bring untold benefits.

President Trump has made the threat of Democratic rule the centerpiece of his closing argument for the midterm elections, warning voters that the left will unleash a wave of violent crime, illegal immigration, higher taxes and cultural upheaval if they win control of Congress.

The former FBI director, a longtime target of the president, has not been indicted in the latest case against him.