Senate Majority Leader Harry ReidHarry Mason ReidAmendments fuel resentments within Senate GOP Donald Trump is delivering on his promises and voters are noticing Danny Tarkanian wins Nevada GOP congressional primary MORE (D-Nev.) approached Former Defense Secretary Robert Gates about becoming then-Sen. Barack Obama's running mate in the 2008 election, according to an excerpt of Gates’s memoir obtained by CNN.

In an exchange that Gates describes as "so weird," he recounts the Nevada lawmaker calling him to conduct an informal vetting.

"It took a lot of willpower for me to keep from bursting out laughing," Gates writes. "He asked me if I had a public position on abortion; I laughed, saying no. He asked if I was a longtime Republican. I said, actually no; I hadn't been registered with either party for many years. He asked how long I had been an academic."

Gates writes that Reid wanted to keep the conversation "very private" and warned that "possibly nothing will come of it."

"I couldn't figure out if he was serious, if it was just idle flattery, or if he was delusional," Gates said.

Reid was asked about Gates's claim at a press briefing on Thursday and answered coyly, "It’s possible."

Obama went on to select Delaware Sen. Joe Biden as his running mate.

Much of the early attention surrounding Gates's book has focused on his harsh criticism of Biden, who he blasted as being "wrong on nearly every major foreign policy and national security issue over the past four decades."

On Wednesday, White House press secretary Jay Carney defended the vice president, calling him "one of the leading statesmen of his time" and "an excellent counselor and adviser to the president."

"He’s played a key role in every major national security and foreign policy debate and policy discussion in this administration, in this White House," Carney said.

— Alexander Bolton contributed

— This post was updated at 12:56 p.m.