Scott Brown, a former U.S. ambassador to New Zealand and Samoa who also served in the Senate representing Massachusetts, is launching a bid to challenge Rep. Chris Pappas (D-N.H.) for retiring Sen. Jeanne Shaheen’s (D-N.H.) seat next year.

Brown used his first ad to tout his background, praise Trump and tie Pappas to former President Biden.

“New Hampshire is an amazing place to live, work and raise a family. We’ve been blessed by two great governors, Chris Sununu and Kelly Ayotte, but in Washington, we haven’t been represented by the right people,” Brown said in the ad. “For four years, Chris Pappas has stood with Joe Biden as he opened the border, drove up the cost of everything and made life just simply unaffordable.”

In a post on X, Pappas responded to Brown’s entry into the race projecting confidence for his campaign.

“It’s official: MAGA loyalist Scott Brown just announced he’s running to flip this seat red,” Pappas said. “New Hampshire rejected him before, and we can do it again.”

Brown’s entry into the race was long expected and he’s the most high-profile Republican to run for Shaheen’s seat. Former Gov. Chris Sununu (R) has teased the idea of a potential run, later opting against it entirely despite being a formidable challenger for the party.

Brown represented Massachusetts in the Senate between 2010 and 2013, later losing reelection to Sen. Elizabeth Warren (D-Mass.) in 2012.

The former ambassador to New Zealand and Samoa later vied for Shaheen’s seat in 2014 but was defeated by the state’s senior senator by over 3 points that fall. Shaheen insinuated that Brown was a carpetbagger, noting his previous residency outside the Granite State.

Brown is likely to run into some of the same criticism again, though an open seat could offer an easier path for the Republican this time around.

The nonpartisan election handicapper Cook Political Report rates Shaheen’s seat as “lean Democrat.”