Chris Pappas, the four-term Democratic congressman, has won New Hampshire’s US Senate race, protecting the open seat from a Republican flip in a closely fought contest against John Sununu, the former senator.

Pappas, 46, is a centrist voice in the US House who has at times broken with his party on major legislation. He focused his Senate campaign on serving as a bulwark against the Trump administration, which is unpopular in the Granite State. Pappas will be the first out gay man to serve in the US Senate.

The race became a late source of anxiety for Democrats, with Pappas, a moderate, locked in a neck-and-neck battle with Sununu to succeed Jeanne Shaheen, the retiring Democratic senator.

Pappas secured endorsements from several prominent Democrats and portrayed Sununu, who once called Donald Trump a “ loser ”, as a faux moderate who would ultimately rubber-stamp the president’s agenda.…