Top aides to President Obama researched and debated replacing Vice President Joe BidenJoseph (Joe) Robinette BidenProgressive rise is good news for Sanders, Warren Biden says 'enough is enough' after Santa Fe school shooting Zinke provided restricted site tours to friends: report MORE with Hillary ClintonHillary Diane Rodham ClintonDem targeted by party establishment loses Texas primary Penn to Hewitt: Mueller probe born out of ‘hysteria’ Trump claims a 'spy' on his campaign tried to help 'Crooked Hillary' win MORE to boost the president’s re-election chances, according to excerpts of a new book obtained by the New York Times. 

Former Obama chief of staff William M. Daley, spooked by the president’s drooping poll numbers in fall of 2011, ordered campaign staffers to poll and focus group the impact of switching Biden for the then-Secretary of State.

“I was vocal about looking into a whole bunch of things, and this was one of them,” Daley told the Times.

“You have to remember, at that point the president was in awful shape, so we were like, ‘Holy Christ, what do we do?′ ”

Aides to Obama ultimately decided that the move would not provide enough of a political boost to justify the shift.

The story is among the biggest revelations in “Double Down,” the latest book from journalists Mark Halperin and John Heilemann. The pair were the authors of the 2008 campaign book “Game Change.”

The book also reveals that Biden, who has admitted publicly to considering a 2016 presidential bid of his own, attempted to meet with Silicon Valley and Hollywood “heavyweights” to aid his own ambitions while fundraising for the president.

According to the book, Biden was chastised by Obama campaign adviser David Plouffe.

The book also reported that Jon M. Huntsman Sr. — the father of the Republican presidential candidate of the same name — was the one who told Senate Majority Leader Harry ReidHarry Mason ReidMcConnell not yet ready to change rules for Trump nominees The Hill's Morning Report — Sponsored by CVS Health — Trump’s love-hate relationship with the Senate Trump to press GOP on changing Senate rules MORE (D-Nev.) that GOP presidential nominee Mitt Romney had avoided paying income taxes for a decade.

Reid regularly repeated the charge during the campaign, daring Romney to release his tax returns. The Romney campaign was reluctant to do so, nervous that the candidate’s personal wealth would alienate voters. But ultimately, the former Massachusetts governor released a notarized statement from his accounting firm attesting that he had paid income taxes in each of the years in question.