Vice President Joe Biden seriously considered throwing his hat in the ring of the 2016 presidential campaign, but ultimately decided not to after the death of his son, Beau Biden, from brain cancer in May 2015.

In the new book “Shattered: Inside Hillary Clinton’s Doomed Campaign” by Jonathan Allen and Amie Parnes (Crown, out now), the authors reveal that before Beau got sick, the Biden family was focused on the son’s future political prospects.

“The elder Biden didn’t want to interfere with his son’s political ascent and worried that his own presidential bid would make it harder for Beau to win statewide office in Delaware [they would have been on the ballot at the same time if Joe ran for president and Beau ran for governor in 2016],” write Allen and Parnes.

When he was on his deathbed, his face partially paralyzed, Beau reportedly pushed his father to make a final run for the Oval Office. His son’s request made him consider again the issue of whether to run, something he’d been weighing for months, if not years.

Biden was irritated that “the media focused so much attention on Hillary and her second bid for the presidency when he was sitting in plain sight in the White House,” they write. “He was also being overlooked by the president whom he had faithfully served, a painful if silent rebuke. Obama and his aides refused to take sides publicly, and some still had no appetite to help Hillary. But few thought Biden, who would turn seventy-four the month of the 2016 election, was the right person to represent Democrats in the campaign.”

Biden knew that he would face considerable challenges raising money against Clinton, partly because many top Democrats were already committed to Hillary. He also knew it would be difficult to recruit top talent because Clinton had already engaged most of the party’s best operatives. That didn’t mean Clinton’s camp wasn’t worried.

One trusted Hillary confidante said at the time: “I don’t know how he gets in without looking like he knocked over the only girl that’s been viable in our entire lives. That’s a big, bad thing to do, especially when they occupy the same space on the spectrum.”