The open Democratic seat is among the 10 most competitive to flip, an outcome that would likely dash Democrats’ hopes of retaking the Senate.

The state has not elected a Republican to the Senate since 2010. But Chris Pappas, the likely Democratic nominee, anticipates a tough race against a well-known opponent, John E.…

Trump has backed former GOP Sen. John Sununu in the Senate primary, in which Democratic Rep. Chris Pappas faces a democratic socialist.