Joe Sestak, a former Pennsylvania congressman, has ended his Democratic presidential primary campaign and his bid for president.

"I could never pay enough for what I experienced, and the men and women I met. ... I will miss the opportunities I had in experiencing America in such a wonderful way!" he wrote in a statement to his supporters.

Sestak is a retired three-star admiral in the U.S. Navy and served on the National Security Council under President Clinton.

At the start of his campaign, he broke down what his first 100 days in office would look like if he were elected president.

"The very first day, I will hold a town hall in the middle of America, open to everyone who can fit in. Former Trump supporters, former Clinton supporters, because I think what people most want in their leader is someone who is accountable to them above party, above any special interest and above one's self. And then I'll fly over to France, and convene the nations — preplanned — of the Paris Accord, and increase, as well as enforce, those types of national commitments that begin to stop the world's greatest threat to humanity: climate change," he said at the time.

"And on my way back, I will announce 'training for a lifetime.' I understand the challenge with student loans. But what about the labor force, the enlisted men and women, so to speak, of ships. Those who work with their hands and their minds. We need to do what we do in the military, is we train and retrain. When an airplane goes out of service, we don't kick them out, like out of a coal mine. We train and retrain them," he continued.

"And then when I land, I'll probably walk along to a gun show, and just walk through, maybe with retired [United States Marine Corps lieutenant colonel Oliver] North … and I'll state upfront how I feel about [gun control], but I know [guns are] valued. And finally, I will go walk into a mosque. I want people to understand that their president values every member of the ship, because we don't get to choose who comes aboard a ship. We work with everyone."