By Edward-Isaac Dovere, Gabriel Debenedetti and Annie Karni

ST. LOUIS — In the final days before Tuesday’s primaries, Bernie Sanders was closing fast in the polls in three of the five states voting, raising the prospect of yet another indecisive Democratic election night, this one marked by Hillary Clinton bolstering her delegate lead but Sanders performing well enough to slingshot into what his campaign argues will be its most important stretch yet.


The Vermont senator’s best-case scenario Tuesday has him pulling out three victories — he’s within single digits of Clinton in the latest polls in Illinois, Missouri and Ohio — an outcome that would rattle the race and raise new questions about the durability of the Clinton campaign.


Even if Tuesday doesn’t significantly alter the delegate math that makes Clinton the prohibitive front-runner, a strong Sanders performance in the industrial Midwest would make possible the long campaign that the senator and his aides switched to after their big and unexpected loss in the Nevada caucuses.


Few large caucus states are left on the map, but seven states are up between March 15 and April 5, including the Arizona primary, four caucuses — in Idaho, Utah, Alaska and Washington — where the Vermont senator is hoping to pick up steam again, and a sixth primary — Wisconsin — where he’s expecting a big win to cap off the two-week run. (Hawaii, caucusing on March 26, is rarely included in the calculus.)

Sanders is expecting to rely on his robust online fundraising operation, which has shown no public signs of slowing down — it raised $5 million in the day after polls closed in Michigan — even as the campaign burns through money rapidly to scale up across the country.


As for Tuesday, Sanders aides believe their best shot is here in Missouri, and the Clinton campaign tends to agree.


But, campaigning Monday, he also projected potential wins in Ohio and North Carolina, provided there’s “a very, very, very large turnout” that he tried to juice Monday with a rally in Charlotte. He’s hoping the state’s large student population and outspending Clinton by $1 million in television ads will help him close the gap.


At her one Chicago rally on Monday, Clinton was full of more anxiety than confidence.


“I’m told I should talk with a very calm and measured voice,” Clinton joked. “I should not get carried away with my intense feelings about what is going on in the country. So I do try and remind myself of that. I try to lower the volume when I remember, but I’m so worried about my country.”


Meanwhile, Clinton’s allies expressed less confidence about Ohio than they have been projecting in recent weeks. Top surrogate Tim Ryan, an Ohio congressman, admitted that with Sanders hammering his message of opposing multinational trade deals that put the senator over the top in Michigan, “I think it’s going to be very close.”


Part of Clinton’s problem, Ryan predicted, might be Donald Trump: In Ohio’s open primary, reasonable-minded Democrats worried about Trump may vote for GOP Gov. John Kasich rather than casting their votes for Clinton.


“If this were a normal year, I would think Hillary would do very well,” he said. “But there’s a lot of people who want to stop Trump.”


In Illinois, Sanders has pulled ahead by 2 points in the latest CBS News/YouGov poll — after trailing by more than 40 in a Chicago Tribune poll as recently as last week — and he’s been leaning in hard there with attacks on Chicago Mayor Rahm Emanuel, whom he’s linked to Clinton. He’s hoping for support among labor too — his adviser Larry Cohen, former president of the Communication Workers of America, has been rallying workers around the state, including at the Nabisco factory closing on the South Side.


Clinton’s campaign, however, predicted a blowout victory in Florida that would once again deliver Clinton a large delegate win — and one that would serve as a necessary cushion as the calendar turns to Sanders-friendly terrain over the next month.


Clinton spent most of her Monday in Illinois meeting voters in small groups. She made a stop at a memorial for children lost to gun violence, laying a bouquet of white roses on the memorial that included 501 names, and prayed with some of the mothers of those lost children, and the Rev. Jesse Jackson.


She also spoke with union workers about how to keep jobs at Nabisco from going abroad. She then flew to Charlotte for the first of two evening rallies in North Carolina.


But it is Florida that she is counting on to be able to call Tuesday night a win, and which would give her cause to say that the upcoming caucus states expected to favor Sanders can’t help him make up the delegate difference.


Sanders still has an uphill delegate battle even as his campaign racks up states in the “win” column: While nearly 700 delegates are at play on Tuesday, Florida is the state with the most, and Missouri with the least. And even the most optimistic Sanders projections have him battling to effective ties in Illinois and Ohio.

The Clinton campaign says the lessons learned from her 2008 race prepared them for a long race from the outset.


“It was apparent relatively early on that Sen. Sanders was going to have a committed support and a lot of resources, so we have planned for that,” Clinton campaign communications director Jennifer Palmieri said after the Democratic debate in Miami last week. “As the Republicans wrap up, you want to make sure that their nominee, particularly if it’s Donald Trump, is being dealt with, but we’ve always expected and built a plan.”


That means fighting in some places where they didn’t expect much of a fight, and shifting to an argument about how this is great for building the Democratic Party and strengthening Clinton for the general, even if some of those races are in never-blue territory like Idaho.


“What’s problematic for us if we start failing to win delegates,” said Clinton campaign chair John Podesta. “Some places favor him, some places favor us.”

Following the model it used in Nebraska, where Sanders won comfortably but netted only five pledged delegates, the Clinton team has made sure to build up organizations in these states. It has focused on the ones with the biggest delegate pools — like Washington — as a way to minimize Sanders’ gains through this stretch.


But Sanders’ campaign figures national news coverage will swing back to his favor if he can rattle off a string of wins, as he incrementally chips away at Clinton’s delegate lead.


New York on April 19 would be the next big prize after March. Clinton’s Brooklyn team contends that her home-state advantage — plus the large minority population — makes it a serious uphill climb for Sanders, and that a similar story plays out in some of the southern New England and mid-Atlantic states voting around the same time, like Maryland and Pennsylvania. But to Sanders, a close race, or even a win, in a progressive stronghold like New York would send shock waves through the front-runner’s base of support.


The Sanders campaign is hoping such an outcome would drastically change the dynamic of the race, drowning out Clinton’s steep advantages in delegate-heavy neighboring states like New Jersey. If it works, that could accelerate Sanders’ push for delegates through largely white states like Kentucky and West Virginia in May, leading into early June, where the Sanders campaign hopes a win in California could finally allow him to take a delegate lead for the first time.


“People say Obama was never this far behind,” said Sanders strategist Tad Devine, “but — well, California, New York and New Jersey were on Super Tuesday last time too.”