Former Vice President Joe Biden reportedly thinks only one Democrat has a shot at defeating President Donald Trump in 2020: Joe Biden.

Politico reports that "multiple people who've been in touch with the former vice president and his team" claim that Biden is moving closer and closer to running against Trump when he comes up for re-election, although a spokesperson for Biden declined to comment.

"He's a great respecter of fate," said one unnamed person close to Biden. "At some point, it may turn into fate and planning."

Biden decided against running for president in 2016 after the death of his son, Beau, the year before. Next week, the former vice president begins a book tour for his new memoir about his relationship with his son. According to some sources close to Biden, this could be a test-run to see if the septuagenarian is ready for a presidential campaign.

"Right now, he's pretty laser-focused on the book tour. Get through that and go see what we can do in '18, and see where things are then," one person who's kept in touch with Biden's advisers since leaving a federal post in January.

Biden's tour will last through December, and will take him across the country, with stops in New York, Massachusetts, Tennessee, Wisconsin, Texas and Michigan. He then plans to spend the first quarter of the new year fundraising for Senate candidates and possibly for House and state parties.

"The VP is out working furiously to support and promote Democrats at all levels because he believes the future of the party is bright," said another person close to Biden.

"If someone emerges that the former VP believes can beat [Trump], I think he is at peace with that," a former donor to Hillary Clinton who is friendly towards Biden told Politico. "On the other hand, if that person doesn't exist or doesn't run, you can expect Joe Biden to take a very serious look."