By Christopher Rosen
October 21, 2015 at 05:07 PM EDT
Leigh Vogel/WireImage

Following months of speculation, Vice President Joe Biden announced on Wednesday that he will not run for president in 2016.

“Unfortunately, I believe we’re out of time,” Biden said during a press conference in the Rose Garden of the White House. “The time necessary to mount a winning campaign for the nomination.”

Biden’s son, Beau Biden, died in May from brain cancer. On Wednesday, as he had previously, the vice president said the grieving process played a part in his decision to not run.

“I don’t think any man or woman should run for president unless, No. 1, they know exactly why they would want to be president, and No. 2, they can look at the folks out there and say, ‘I promise you that you have my whole heart, my whole soul, my energy and my passion to do this. And I’d be lying if I said that I knew I was there,” Biden said during an interview with Stephen Colbert back in September. “I’m being completely honest. Nobody has right, in my view, to seek that office unless they’re willing to give it 100 percent of who they are. I’m optimistic, I’m positive about where we’re going […] it just sometimes overwhelms you.”

On Wednesday, Biden said one of his ultimate goals was to spearhead the search for a cancer cure.

“I believe we need a moonshot in this country to cure cancer. It’s personal,” Biden said. “But I know we can do this. If I could be anything, I’d want to be the president that ended cancer, because it is possible.”