She had eight candidates to choose from, but Sen. Maggie Hassan said Chris Pappas is her choice in the wide-open race for the Democratic nomination to succeed retiring U.S. Rep. Carol Shea-Porter.

“Chris Pappas has just a terrific record of bipartisan problem-solving that’s very result-driven, and he’s shown results from it,” Hassan said.

Hassan endorsed the three-term executive councilor from Manchester on Wednesday at a campaign event at the Water Street Bookstore in Exeter, close to the senator’s home in Newfields.

Pappas was elected to the five-member Executive Council in 2012, the same year Hassan won the governorship. During Hassan’s four years in the corner office, Pappas was a reliable ally on the council.

Pappas said he was proud to earn Hassan’s endorsement.

“While she was governor, we worked together to help expand health coverage and deliver additional resources to invest in treatment and recovery, and I would be honored to join her as a member of the delegation and fight for New Hampshire values in Washington,” he said in a statement.

The other Democrats in the 1st District race are Maura Sullivan of Portsmouth, a retired U.S. Marine and Iraq War vet who served at the Veterans Administration and the Pentagon under President Barack Obama; state Rep. Mark Mackenzie of Manchester, a former fireman who served more than two decades as head of the state chapter of the AFL-CIO; retired Portsmouth trial lawyer Lincoln Soldati, a former Somersworth mayor who also spent 17 years as Strafford County attorney; state Rep. Mindi Messmer of Rye, an environmental scientist; Iraq War veteran and current Rochester City Attorney Terence O’Rourke; and technology executive and community activist Deaglan McEachern of Portsmouth.

Levi Sanders, the son of U.S. Sen. Bernie Sanders of Vermont, jumped into the race for the Democratic nomination in February. The legal services analyst lives in Claremont, which is in New Hampshire’s 2nd District.

Hassan’s endorsement is the first by one of the top Democrats in the state. Sen. Jeanne Shaheen has yet to make an endorsement. And Shea-Porter, the retiring four-term incumbent, also remains neutral to date.

The endorsement is being criticized by one Pappas’s rivals.

O’Rourke claimed that the endorsement “shows desperation on the part of the establishment because their chosen candidate isn’t gaining traction.”

Pappas is viewed by some progressive activists in New Hampshire as the state Democratic establishment’s candidate in the race.