Vice President Joe Biden has already signaled that he regrets not running for president in 2016, but when asked if he would reconsider his decision, he left the door open.

“I’ve learned never to say no, but I can’t imagine,” he told TODAY’S Savannah Guthrie Tuesday.

“If I win the lottery maybe. … Everyone says I’m going to retire. Well, I’ll run if I …” he joked, admitting that he had not bought a Powerball ticket.

He stated that being President of the United States was not a dream of his, but that it would be hard to step away from politics–since he has served in some political office since he was 28.

“Every morning, I’ve gotten up, and I’ve had some policy concern that was on my mind that I was able to work on to try and change things,” he said. “And it’s hard to figure what replaces that, that sense of purpose when you’re not in this office,” he said.

He said he was not trying to diss Hillary Clinton by praising Bernie Sanders for his record of opposing income inequality.

“This has been Bernie’s mantra. … Even when income inequality wasn’t as serious as it is today, it was his drumbeat,” Biden said. “Bernie is pushing the envelope on this.”