(CNN) — President Barack Obama's closest advisers secretly considered replacing Vice President Joe Biden with Hillary Clinton on the 2012 ticket, according to the New York Times.
The revelation is the most notable bombshell from Mark Halperin and John Heilemann's heavily anticipated 2012 campaign tome, "Double Down: Game Change 2012." The Times obtained a copy of the forthcoming book and reported Thursday evening that the President's top aides conducted "extensive group-sessions and polling in late 2011" to gauge whether the dumping Biden could help bolster Obama's waning re-election hopes.
According to the Times' national political correspondent Jonathan Martin, the book provides a thorough account of the effort by senior officials inside the campaign and the White House, namely former White House Chief of Staff Bill Daley, to measure what effect swapping former Secretary of State Clinton for the Vice President would have in the polls.
The potential switch was a closely guarded secret within the Chicago campaign infrastructure and inside the Oval Office. Only half a dozen of the President's closest advisers -- including Daley, former Obama campaign chief Jim Messina, and former White House senior advisers David Axelrod and David Plouffe -- knew the change was under consideration.
"Double Down" claims Daley spearheaded the effort to replace Biden, despite their "close personal rapport," before ultimately deciding against the move when their data showed adding Clinton to the ticket wouldn't "materially improve Obama's odds."
In an interview with Martin, Daley confirmed that the administration did in fact consider replacing Biden with Clinton.
"I was vocal about looking into a whole bunch of things, and this was one of them," Daley told the paper. "You have to remember, at that point the President was in awful shape, so we were like, 'Holy Christ, what do we do?'"
While Daley characterized the research as "due diligence," Martin told CNN's Anderson Cooper that the re-election campaign made a significant investment in finding out whether the move would pay dividends at the polls.
"Campaigns don't spend the kind of money on polling and focus groups unless they're seriously considering something," Martin said on AC360.
It's unclear, however, whether Obama knew his team was exploring the swap. Martin told CNN that he asked Daley whether his then-boss knew about the potential shuffle. While Daley said he doesn't think the President "was aware" of the potential change, the former chief of staff admitted that it's "possible" Obama knew.
Martin added that "Double Down" does not definitively answer whether the political probing reached Obama's desk.
Cooper asked Martin whether he seriously thought Obama did not know about the research into dumping Biden from the ticket.
"Possibly," Martin replied.