Heidi M. Przybyla

USA TODAY

Bernie Sanders scored a surprise upset over Hillary Clinton in Michigan on Tuesday, though she was expected to widen her delegate lead over the Vermont senator by winning Mississippi by a wide margin.

Sanders did not heavily contest Mississippi but saw Michigan as a chance to renew his momentum heading into other critical contests this month.

“What tonight means is that the Bernie Sanders campaign, the people’s revolution that we are talking about,” Sanders said, “is strong in every part of the country.”

“Whether we win or lose tonight in Michigan, basically the delegates here are going to be split up," said Sanders, who spoke from Florida.

Having lost by huge margins to Clinton in the South, Sanders had fallen far enough behind in convention delegates that he’d have to bag three-fifths of remaining delegates just to break even with Clinton, according to the nonpartisan Cook Political Report. Delegates are divided proportionally in each state based on the primary results. Still, his Michigan victory undercuts the Clinton campaign's argument that Sanders is not competitive in larger, industrial states.

At an evening rally in Cleveland before the Michigan results were announced, Clinton kept her criticism focused on Republicans instead of Sanders.

“I’m proud of the campaign that Sen. Sanders and I are running,” she said. “We have our differences as you can see when we debate,” she said.

“Those differences pale in comparison to what’s happening on the Republican side. Every time you think it can’t get any uglier they find a way,” said Clinton. “As the rhetoric keeps sinking lower, the stakes in this election keep getting higher.”

Clinton's Mississippi victory was no surprise. She had done very well among African-American voters throughout the primary season, and both states were expected to have large numbers of black primary voters. But her enormous margin of victory there, capturing well over two-thirds of the vote, served to pad her delegate lead even before the Michigan results were final.

Michigan is ideally suited to Sanders’ anti-trade, anti-corporate message about a “rigged economy," and he lobbed a series of attacks on Clinton, including an ad featuring boarded-up homes in Michigan covered in graffiti and shuttered factories.

The city of Detroit has gone from one of the country’s richest in the 1960s to one of the poorest today. The once-thriving automotive hub is pocked by blighted homes and crime. The loss of manufacturing jobs has also devastated many neighboring cities, fueling more than 20 years of resentment among white, working-class Democrats over the North American Free Trade Agreement, signed into law by Clinton's husband, former president Bill Clinton, in 1993.

Sanders has been targeting young voters and disaffected white, working-class voters hurt most by the decline of the automotive industry over the past 20 years. While Clinton is also competing for this demographic, major labor unions including the Teamsters and United Auto Workers, traditional Democratic allies, have not endorsed a candidate. Early election results showed her advantage in the metro Detroit area was not enough to overcome Sanders' strength statewide. He even performed well in the Flint area despite Clinton's efforts to champion the city's water crisis.

Speaking to the press, Sanders took a swipe at the "pundits" who said "Bernie Sanders was not going anywhere." Then he followed up with a tweet.

Clinton went on offense during a Sunday debate during which Sanders defended legislation granting gun makers legal immunity for damages caused by their products, a hot issue in the black community. She also criticized Sanders for his vote against a 2009 government bailout that many in Michigan credit for saving the automotive industry and 4 million jobs.

During a Fox News town hall on Monday, Sanders defended his vote by saying he supported the auto package, but not the broader legislation it was attached to. "I knew at the time, that if that industry went down, millions of jobs, not only in Michigan and Ohio, but all over this country would be impacted," said Sanders. "What I did not vote for was the bail out of Wall Street," he said.

Clinton has also been trying to distance herself from her husband’s trade policies, including granting China "most favored nation" trading status, by pointing to her Senate record. Clinton says she opposed a Central American trade pact, the only multinational trade agreement to come up during her Senate tenure, and more recently, she came out against the Trans-Pacific Partnership, a deal President Obama has been trying to advance.

Days before the primary, she proposed a “clawback tax” on companies that send jobs or production facilities overseas. Clinton's poor showing in Flint is particularly notable since she pushed for the debate there last Sunday on CNN to give the issue more national attention.

Sanders, Clinton take on Flint water crisis in Democratic debate

Clinton went into Tuesday's primaries leading Sanders among pledged delegates by 673 to 477, underpinned by big margins she has racked up among black voters in Southern states and Latinos in Texas. Mississippi exit polls showed six in 10 voters were African American, and Clinton took 90% of that demographic.

Until now, Sanders’ wins have been concentrated in caucus states like Minnesota and Colorado, as well as his home state of Vermont. Accounting for superdelegates, the party leaders and officials who automatically get convention votes, Clinton led Sanders going in to Tuesday's contests 1,134 to 502. A candidate needs 2,382 delegates to clinch the nomination.

Clinton is leading Sanders by a large margin in Florida, a state that’s played a historically decisive role in determining presidential winners. Both Ohio and Florida vote March 15, and the big question will be whether Sanders can extend his Michigan victory to Ohio.

During Monday's Fox News town hall event, Clinton sought to look ahead to the general election, calling Sanders an "ally" in response to an audience question. "I hope to work with him, the issues he has raised, the passion he has demonstrated, the people he has attracted, are going to be very important in the general election," she said.