DETROIT -- Bernie Sanders won the Michigan Democratic primary on Tuesday night in an upset that delivers a sharp blow to Hillary Clinton's hopes of quickly securing her party's nomination.
Sanders' victory, on the eve of the next Democratic debate, will send a jolt of new excitement through his campaign and raise fresh questions about Clinton's operation.
The former secretary of state easily beat Sanders in the Mississippi primary -- a victory that further extends her control of the South -- but her Michigan loss underscores her struggle to answer attacks by the Vermont senator on her links to Wall Street.
The Michigan results also suggest Sanders' message of economic populism will play well in upcoming primaries in Rust Belt states such as Ohio, Illinois and Wisconsin.
On the Republican side, Donald Trump won the Hawaii caucuses. He also won Republican primaries in Michigan and Mississippi, important victories that propel him closer to the nomination. Texas Sen. Ted Cruz won the Idaho Republican primary.
The contests came on what was dubbed Super Tuesday 2. Republicans were competing in four states with 150 delegates up for grabs. Democrats were fighting for 166 delegates in Michigan and Mississippi.
Clinton holds an overall lead of about 200 pledged delegates over Sanders, whose spirited campaign has enlivened grass-roots Democrats and tugged Clinton to the left on some key issues.
While the Michigan defeat isn't likely to seriously dent her lead in delegates, it's an embarrassing speed bump in the candidate's efforts to pull away from Sanders.
Sanders: 'Our strongest areas are yet to happen'
Sanders thanked Michigan voters for "repudiating" polls that indicated Clinton had stronger support in the state.
"What tonight means is that the Bernie Sanders campaign, the people's revolution that we're talking about, the political revolution that we're talking about, is strong in every part of the country," Sanders said. "And, frankly, we believe our strongest areas are yet to happen."
Clinton and Sanders have clashed repeatedly in recent days over issues that are vital to Michigan voters. Clinton hammered her rival over a vote against a bailout for the U.S. auto industry in 2009, while the Vermont senator lambasted her over her past support for free-trade deals which he said sowed ruin in the Midwest.
There is second guessing among some Democrats that some people in Clinton's organization started looking beyond the primary to a general election contest against Trump.
"They didn't take Sanders for granted as much as voters," said one top Democrat close to the campaign.
"The sooner I could become your nominee," Clinton told supporters on Monday, "the more I could begin to turn my attention to the Republicans."
Earlier Tuesday, Clinton won the Mississippi Democratic primary, a victory that consolidates her dominance of Southern primary states with high numbers of African-American voters. That's a constituency with which Sanders, who has performed better in less-diverse states, struggles.
Attacks leave Trump undiminished
Trump's strong performance -- he has won 14 states -- suggests his capacity to win is undiminished despite a barrage of attacks by his rivals and the Republican establishment on his personality, his sometimes vulgar campaign style and his fitness to serve as president.
In a news conference Tuesday night, Trump said the results were a repudiation of "so many horrible, horrible things" said about him over the last week, which he said added up to "$38 million worth of horrible lies."
It shows you how brilliant the public is because they knew they were lies," he said.
Heading into Tuesday, Cruz was seeking a strong showing to bolster his claim that he is the only Republican who can stop Trump, and Florida Sen. Marco Rubio was desperate for some evidence to counter an impression that his campaign is fading.
Ohio Gov. John Kasich's only hope of becoming the GOP nominee appears to rest on corralling establishment support if Rubio exits the race and hoping a convention fight could deprive Trump of the nomination.