Mike Bloomberg's campaign is sounding the alarm that Bernie Sanders will soon amass an unsurmountable delegate lead if the Democratic field stays split — and took the extraordinary step of suggesting laggards should drop out.

What they're saying: Kevin Sheekey, Bloomberg's top strategist, said: "The fact is if the state of this race remains status quo — with Biden, Pete and Amy in the race on Super Tuesday — Bernie is likely to open up a delegate lead that seems nearly impossible to overcome."

"I don’t think many people understand the dire circumstances here."

Why it matters: Based on every national poll, plus steady access to money, Sanders is the indisputable — if underappreciated — frontrunner.

The Bloomberg campaign got high-profile validation of its theory:

David Plouffe, Barack Obama's 2008 campaign manager, tweeted in response to Nate Silver's delegate projections through Super Tuesday — which show Sanders with 41%, followed by Bloomberg and Joe Biden with 18% each.

"If this happens, Sanders would have a pledged delegate lead he’ll never relinquish."

In a "State of the Race" memo to Bloomberg gurus Sheekey and Howard Wolfson, senior adviser Mitch Stewart and states director Dan Kanninen argue:

"If Biden, Buttigieg, and Klobuchar remain in the race despite having no path to appreciably collecting delegates on Super Tuesday (and beyond), they will propel Sanders to a seemingly insurmountable delegate lead by siphoning votes away from [Bloomberg]."

Read the memo.