HILLARY CLINTON bested rival Bernie Sanders in seven Super Tuesday states, strengthening her momentum as she marches toward the Democratic presidential nomination.

Propelled in part by a sweep of Southern states with large black voting populations, Clinton is now on a path toward a permanent lead among delegates that will be hard for Sanders to surmount. Her performance in 12 states and territories Tuesday was expected to dramatically widen that lead as she tries to put to rest any lingering doubts over her shaky start in the 2016 voting.

Sanders had been declared the winner in home state of Vermont, Oklahoma, Colorado and Minnesota.

Signaling her confidence, Clinton set her sights on GOP front-runner Donald Trump as she addressed supporters during a victory rally in Miami.

"It's clear tonight that the stakes in this election have never been higher and the rhetoric we're hearing on the other side has never been lower," she said.

When she took the stage on Tuesday, Clinton sounded very much like a general-election candidate - decrying the tenor of the Republican nomination contest and laying out the issues, including income inequality, on which she intends to run.

"This country belongs to all of us, not just those at the top, not just to people who look one way, worship one way or even think one way," she said.

Sanders, standing with his wife, children and grandchildren in Essex Junction, Vt., said that while he wants to win in every part of the country, it was meaningful that "the people who know me best . . . have voted so strongly to put us in the White House."

The socialist senator vowed to stay in the race until voters in all 50 states have a say, noting that by the end of the night, only 15 states will have weighed in.

More delegates were up for grabs on Super Tuesday than on any other single day on the Democratic nominating calendar.

Clinton had been widely expected to win Tuesday in six Southern states, including Virginia, that were considered a "firewall" of African-American support with the power to blunt a Sanders surge that had carried him to an effective tie with Clinton in Iowa and a 22-point victory in New Hampshire. Clinton began regaining momentum after a five-point victory in Nevada's Democratic caucuses - and a trouncing of Sanders by nearly 50 points in South Carolina.

She was immediately declared the winner in Georgia and Virginia when polls closed at 7 p.m.; Alabama, Arkansas and Tennessee came next. She was far ahead in Texas, according to early returns, while she and Sanders appeared neck and neck in Massachusetts.

"Experience" was the top candidate quality Virginia voters preferred, picked by more than a third in preliminary exit poll data, and Clinton won those voters by about 90 points.

Black voters, who make up about a quarter of the Democratic electorate in Virginia, supported Clinton by a 60-point margin in the state. Clinton also led among white voters but much more narrowly in early results - about 10 percentage points.

Sanders's only winning age group in Virginia was voters younger than 30, which he won by roughly 40 points.

Sanders had concentrated on five states that voted Tuesday - Colorado, Minnesota, Oklahoma, Massachusetts and Vermont. All have whiter voting populations, and most have a liberal bent.

Because of Democrats' system of awarding delegates proportionally, Sanders will collect significant numbers of delegates even in states he loses.

He reminded his audience of that Tuesday, telling supporters that "by the end of tonight, we are going to win many hundreds of delegates."

Sanders had been expected to do well in Minnesota's caucus format. But Clinton's late decision to make a caucus-day campaign swing in the state showed that she considered it competitive.