The Note: Super shakeups rock Super Tuesday as delegate math looms large

The TAKE with Rick Klein

Joe Biden has his momentum. Bernie Sanders has his movement. Michael Bloomberg has his money. And Elizabeth Warren has her motivation.

Those forces collide in dramatic and campaign-defining fashion on Tuesday, a nationwide explosion of voting that has already narrowed the field in staggering ways.

If it's now a two-way race, it still features four major candidates -- with the front-runner in each ideological lane still having some company. Throw out the polling, along with the spin: This race is all about delegates, starting now.

Notably, with the possible exception of Warren in her home state of Massachusetts, only Biden and Sanders have realistic shots at winning states on Super Tuesday. More critical than states won could be the 15% threshold -- who exceeds it and where, in what looks for now like a pitched battle to accumulate delegates.

The range of possible outcomes derive from stubborn delegate math.

Sanders could emerge with a lead that's all-but insurmountable; Biden could coalesce the Amy Klobuchar/Pete Buttigieg voters into a formidable delegate bloc; or three, or even four, candidates could put significant points on the board, eyeing a contested convention this summer.

Super Tuesday is very unlikely to determine the nominee. But it's very likely to determine the kind of nomination fight ahead for Democrats.

Super Tuesday

(Correction: A previous version of The Note had the incorrect number of delegates up for grabs in Super Tuesday voting. There are 1,344.)

The RUNDOWN with MaryAlice Parks

The last-minute jostling of the race, designed to help Biden, could easily backfire in favor of Sanders.

With former rivals and Democratic National Committee chairs throwing their weight behind the former vice president, the narrative on the eve of the first day of national voting was set: large swaths of the party were ready to united behind one man.

But don't forget -- Sanders is popular, in no small part, because he defies the Democratic Party, not despite of it.

In the last few months his team has joked that attacks from party officials who look just too inside, too Washington, help him more than they hurt.

Sanders' is the longest serving independent in the history of the U.S. Congress and in each state that has voted so far -- even South Carolina where Sanders lost big time -- more Democrats in exit polls said they supported Sanders' signature issue, a universal health care system, than opposed it.

Biden has largely mocked the idea of "Medicare for All" and tangled with voters who have expressed their support for the Green New Deal too. It may have helped him consolidate support, but it could raise a whole new set of challenges for him down the road.

The TIP with Meg Cunningham

A global threat may be entering the political sphere when it comes to coronavirus, but election officials aren't worried that the virus will affect turnout on the single biggest day of voting in the presidential primary. Alabama, Arkansas and Oklahoma, among others, will not put any precautions in place as they relate to the virus. Oklahoma has no-excuse absentee voting and early voting for voters who are concerned about showing up in-person to vote.

California, the most delegate-rich state to head to the polls Tuesday, told ABC News that they do not expect any disruptions when it comes to turnout in polling places.

"In California, there are already multiple options for voters to cast their ballots built right into our system. Over 75% of voters received a vote-by-mail ballot this election -- with a variety of options for ballot return, including by mail, through drop boxes or at polling locations," a spokesperson for the Secretary of State's Office said. "There have also never been more in-person, early voting opportunities for voters in California who require assistance or did not receive a vote-by-mail ballots."

Otherwise, officials are advising polling places to stock up on hand sanitizer for Election Day and treat the threat as they would the flu.

THE PLAYLIST

ABC News' "Start Here" podcast. Tuesday morning's episode features ABC News contributor and former Sen. Heidi Heitkamp, who discusses what Sen. Amy Klobuchar dropping out means for former Vice President Joe Biden, who is racking up endorsements ahead of Super Tuesday voting. Then, ABC News Senior Washington correspondent Devin Dwyer examines the latest movement from the Supreme Court on Obamacare. http://apple.co/2HPocUL

FiveThirtyEight Politics Podcast. The biggest day of the primary cycle is upon us! In this installment of the FiveThirtyEight Politics podcast, the crew previews what is at stake as 14 states, American Samoa and Democrats abroad cast their ballots on Super Tuesday. They also debate how former South Bend, Indiana, Mayor Pete Buttigieg's exit from the race could shape the results. The team recorded the podcast before the news broke that Sen. Amy Klobuchar, D-Minn., would also drop out and endorse former Vice President Joe Biden. https://53eig.ht/2VDhSVT

WHAT YOU NEED TO KNOW TODAY

Download the ABC News app and select "The Note" as an item of interest to receive the day's sharpest political analysis.

The Note is a daily ABC News feature that highlights the key political moments of the day ahead. Please check back tomorrow for the latest.