Heidi M. Przybyla

USA TODAY

Hillary Clinton scored big Rust Belt victories by winning the Ohio and Illinois presidential primaries Tuesday, and she trounced Bernie Sanders in Florida and North Carolina.

Tuesday ended with Missouri too close to call. Clinton clung to a narrow lead as the final ballots were counted, but the margin was too close to certify a winner. Nevertheless, Clinton was assured of expanding her commanding lead over Bernie Sanders in the delegates needed to clinch the Democratic nomination.

“This is another Super Tuesday for our campaign,” Clinton said in a victory speech in Florida, noting she'll net at least 2 million more votes nationwide. “We are moving closer to securing the Democratic Party nomination and winning this election in November.”

Clinton had been expected to win the South, but the bigger battleground was in the Midwest. Her Ohio victory short-circuited Sanders’ hopes of converting a surprise win in Michigan last week to a sweep of industrial states voting on Tuesday. Adding Illinois to the win column means she carried at least four of the five states that voted Tuesday, shifting the narrative back to her inevitability as the Democratic nominee.

Polls had showed Sanders narrowing her advantage in the Buckeye State, and he predicted he would win Ohio. Sanders had also hoped to benefit in Illinois from Clinton's association with unpopular Chicago Mayor Rahm Emanuel. In the end he could not declare a win anywhere.

Sanders urged supporters to keep fighting for a fairer economic and political system, and he pledged to fight on to states including Arizona, which votes next Tuesday.

“Do not settle for the status quo, for the status quo is broken,” said Sanders. “Don’t tell me that we have to have the highest rate of child poverty in the industrial world when we have a proliferation of millionaires and billionaires,” he said. “Don’t tell me that veterans in this country have to sleep out on the street,” he said.

“We can make real change,” he said. “But we don’t make change if they divide us up.”

Democrats award their delegates proportionally in each state, so Sanders will also make gains even if he does not win states. But he is not gaining ground on Clinton.

Tuesday primaries: State-by-state roundups and results

Who won the night? Big moments from Tuesday's primaries

The contest has exposed a populist divide in the Democratic Party as Sanders escalates attacks on Clinton’s record on trade and her paid speeches to Wall Street banks.

Like in Michigan, voter angst over trade deals was expected to help Sanders in other Midwest states, in particular with white, working-class voters in these states hit hard by manufacturing job losses. In her victory speech, Clinton highlighted her manufacturing and infrastructure jobs plans. “We’re going to stand up for the American middle-class again," she said, "and make sure no one takes advantage of us — not China, not Wall Street and not corporate executives."

In an MSNBC town hall Monday night, Sanders said Clinton has supported “virtually all of these trade agreements, which have turned out to be an unmitigated disaster for working class people in this country.”

Clinton has previously defended her record by saying she voted against the only trade agreement to come before her in the Senate.

For her part, Clinton has begun focusing most of her fire on the GOP field. In her speech Tuesday she took several shots at Donald Trump, including that the next commander-in-chief has to “be able to defend our country, not embarrass it."

While Clinton wants to wrap up the nomination as quickly as possible to pivot to the general election, she is still walking a tightrope when it comes to Sanders.

Ahead of the Michigan primary, Clinton attacked Sanders for a vote against a 2009 automotive industry bailout, drawing fire from a visibly irritated Sanders, who said he supported the legislation until it became a Wall Street “bailout.”

Yet Clinton will eventually need Sanders’ help in convincing his supporters to back her, and the longer and nastier the primary is, the harder it will be for the two to come together.

For Sanders, the delegate math continues to work against him.

Clinton began the night with 768 pledged delegates compared with 554 for Sanders. Before Missouri and Illinois results had been declared, she had extended her delegate lead to more than 300 delegates, and that is not counting the nearly 450-delegate lead she has among "superdelegates," the party leaders who are not bound by primary results.