Mark Kelly, an American astronaut and husband of former Rep. Gabby Giffords, is running for US Senate in Arizona in 2020.

Kelly announced on Tuesday that he would seek the late John McCain’s seat, which Sen. Martha McSally was appointed to last year after losing her Senate race to Kyrsten Sinema. The emotional four-and-a-half-minute video starts with Kelly recalling his first sunrise in space, traces his family history, and then turns to Giffords’s shooting in 2011 and the themes on which he will run in the upcoming campaign.

“What I learned from my wife is how you use policy to improve people’s lives,” Kelly says, citing health care, economic stagnation, and climate change as challenges that need to be addressed.

“Solving some of the problems requires one thing, and that’s teamwork,” Kelly says. “Partisanship and polarization and gerrymandering and corporate money have ruined our politics and it’s divided us.”

Kelly’s entrance into the race is a major recruiting win for Democrats as they look to reclaim the Senate majority in the next election. He boasts a strong biography and enjoys a high public profile; though Giffords’s shooting eventually forced her to step down from Congress, she and Kelly have maintained active roles in the public discourse, advocating strongly for gun control measures over the past decade.

Kelly would have to win a Democratic primary, of course, and Rep. Ruben Gallego has openly pondered his own Senate run in 2020. McSally seems like the likely Republican opponent. She will be a quasi-incumbent, appointed after her midterm loss by Gov. Doug Ducey to fill McCain’s seat, temporarily held by Jon Kyl immediately after McCain’s death.

Arizona marks one of the prime Democratic pickup opportunities as they look to flip the current 53-47 Republican Senate majority. Sinema narrowly prevailed there over McSally in 2018, and the state has trended toward Democrats, particularly in presidential election years. Donald Trump won by less than 4 points over Hilary Clinton in 2016.

As of now, 20 Republican-held seats are on the ballot in 2020 — including in states like Arizona, Colorado, Maine, Iowa, North Carolina, and Georgia, where Democrats should at least have a plausible chance of winning the seat away from Republicans. However, they will also have to defend 11 seats, including in deep-red Alabama, where Sen. Doug Jones is up for his first reelection after his shocking special election win in 2017.