Pollster floats Biden rescue plan – but admits all are 'merely possibilities'

Sanders could try to push through a rules change at the Democratic convention that would pry away Clinton's super delegates

Schoen writes that Clinton's inevitability will be 'eviscerated' if she loses California primary next week

Hillary Clinton's limp to the finish line of the Democratic primary is prompting a prominent former pollster for Bill Clinton to declare the once unthinkable could happen and she could lose the nomination.

'The inevitability behind Mrs. Clinton’s nomination will be in large measure eviscerated if she loses the June 7 California primary to Bernie Sanders,' pollster Doug Schoen wrote in the Wall Street Journal late Tuesday. 'That could well happen.'

Schoen, who launched the firm Penn, Schoen & and Berland along with longtime Clinton pollster and confidante Mark Penn, pointed to public polling to make the case Vermont Senator Bernie Sanders could win in California, which would deal a harsh blow to Clinton. He is also a Fox News contributor.

'Even a narrow win would give him 250 pledged delegates or more—a significant boost,' he wrote. 'California is clearly trending to Mr. Sanders, and the experience in recent open primaries has been that the Vermont senator tends to underperform in pre-election surveys and over-perform on primary and caucus days, thanks to the participation of new registrants and young voters.'

Hillary Clinton hopes to wrap up the nomination next Tuesday when New Jersey and California Voters head to the polls

Pollster Doug Schoen writes that Clinton's inevitability will be 'eviscerated' if she loses California

He cites new voter registration statistics – including 1.5 million new Democratic registrants in California since January – more than double the increase for the same period in 2012.

Clinton leads Sanders in pledged delegates and may go over the top with a big win in New Jersey on Tuesday.

But Schoen writes that a loss in California could sap Clinton's momentum and feed a drive to replace her on the ticket.

'A Sanders win in California would powerfully underscore Mrs. Clinton’s weakness as a candidate in the general election,' he writes. 'Democratic superdelegates—chosen by the party establishment and overwhelmingly backing Mrs. Clinton, 543-44—would seriously question whether they should continue to stand behind her candidacy,' he continues.

A Public Policy Institute of California poll take last week gave Clinton just a two-point lead, although an Hoover Institution Golden State poll released this week gave Clinton a healthy 13-point lead.

Bernie Sanders is campaigning across the Golden State this week

Schown writes that after California win, Sanders could try to change the rules at the DNC and require unelected superdelegates to back whichever candidate wins their state's primary or caucus.

'There is every reason to believe that at the convention Mr. Sanders will offer a rules change requiring superdelegates to vote for the candidate who won their state’s primary or caucus,' he writes.

He says such a vote would serve as a 'referendum' on Clinton's candidacy. Schoen predicts Sanders could be within 200 pledged delegates of Clinton if Sanders 'stays competitive' in New Jersey, a state that neighbors Clinton's home state of New York, making the rules change 'more likely.'

'In recent weeks the perception that Mrs. Clinton would be the strongest candidate against Donald Trump has evaporated,' he adds.

The Real Clear Politics poll average has Clinton statistically tied with Trump. 'Bernie Sanders consistently runs stronger than she does against Mr. Trump nationally, beating him by about 10 points in a number of recent surveys,' Schoen notes.

Clinton leads trump by 4 percentage points, 45 to 41, in a Quinnipiac University poll released Wednesday.

Schoen writes about a 'capitulation' to Sanders at the convention, with his outspoken supporters getting named to platform and other committees. There is also the matter of a looming FBI investigation into Clinton's email practices.

'The damning findings buttressed concerns within the party that Mrs. Clinton and her aides may not get through the government’s investigation without a finding of culpability somewhere,' he writes.

Schoen also points to Clinton's high disapproval rating, with voters not trusting her by 4 to 1.

What he doesn't address is Clinton's built in advantage in the electoral college, even if she secures her party's nomination in ugly fashion. Real Clear Politics averages also show Clinton leading Trump in Florida, Ohio, Pennsylvania, and Virginia – states that Trump will have to find a way to win to beat her, even if suffers more humiliation on the way to the nomination.