Clinton and Trump, frontrunners in the US presidential nomination, are seeking to finish off their challengers on Super Tuesday. Support from black voters is a key factor in Clinton's run.
Registered Democrat and Republican party members began voting in primary elections on Tuesday in what is the pivotal day for determining candidates for the November 8 presidential election.
Democrats will vote in 11 states and in the US territory American Samoa on Super Tuesday, with 865 delegates. It will take 2,383 delegates to secure the nomination at the party's national convention in July in Philadelphia.
Republicans will vote in 11 states, with 595 delegates at stake - nearly half the 1,237 delegates needed to gain the nomination at the party's convention in July in Ohio.
Former Secretary of State and First Lady Hillary Clinton began the campaign as the favorite before Vermont Senator Bernie Sanders made a strong showing, gaining support especially from young voters.
Over the weekend, Clinton beat Sanders in the South Carolina primary, securing 86 percent of the African-American vote in her third win in four contests. Should she gain the support of black voters by similar margins in places like Alabama, Georgia and Virginia on Tuesday, it will be hard for Sanders, a self-described democratic socialist, to bounce back.
On Monday, Clinton traveled to several states to urge supporters to turn out in numbers. She turned her attention to the language of the Republican frontrunner, Donald Trump: "I really regret the language being used by Republicans. Scapegoating people, fingerpointing, blaming. That is not how we should behave toward one another," she told a campaign rally at a university in Fairfax, Virginia. "We're going to demonstrate, starting tomorrow on Super Tuesday, there's a different path that Americans ought to take."
In order to stay in the race, political analysts suggest Sanders has to notch up wins in at least five states: his home state of Vermont plus Colorado, Massachusetts, Minnesota and Oklahoma. His campaigners hope to keep the vote close in Virginia. Opinion polls in each of Sanders' March 1 target states are tight.
Clinton is expecting comfortable margins of victory in Alabama, Arkansas, Georgia, Tennessee, and Texas. All of them are states with sizeable African-American populations.
In the ongoing controversy of Clinton's use of a private email server during her time as secretary of state, the US State Department on Monday made public the final batch of emails. Government lawyers have read thousands of mails to see if any contained classified information. They found several that raised questions.
Her opponents have seized on the issue, accusing her of putting security at risk. Reince Priebus, chairman of the Republican National Committee, declared Clinton had "recklessly jeopardized our national security and sensitive diplomatic efforts" and the scandal ought to disqualify her from the presidency.
Trump race controversy
The Republican frontrunner, real estate mogul Donald Trump gathered more controversy around him after he briefly refused to disavow former Ku Klux Klan leader David Duke during a television interview.
Trump said he had not understood the interviewer who first raised the question about Duke and other white supremacists. Trump did later repudiate Duke but his rivals for the nomination, Texas Senator Ted Cruz and Florida Senator Marco Rubio, were quick to criticize.
Campaigning in Virginia, Rubio said "We cannot be a party who refuses to condemn white supremacists and the Ku Klux Klan."
"Not only is that wrong, it makes him unelectable," Rubio added. "How are we going to grow the party if we nominate someone who doesn't repudiate the Ku Klux Klan?" At a campaign rally in Tennessee, where the KKK was founded in 1865 - he warned supporters: US media and Democratic groups will jump on Trump "like the hounds of hell" if he wins the nomination.
Cruz called Trump's comments "Really sad."
"You're better than this," Cruz wrote. "We should all agree, racism is wrong, KKK is abhorrent."
Trump's rally Monday in Radford, Virginia, was repeatedly disrupted by demonstrators chanting "Black lives matter." Trump asked a protester, "Are you from Mexico?" after he was interrupted during remarks about immigration. He ordered several people to be removed, before casting himself as a unifying political force: "Believe it or not, we're going to unify this country," he said.
The dispute brought other Republican senators out against Trump. "This is the party of Abraham Lincoln," Senator Ben Sasse said on Monday. He accused Trump of being a non-conservative plotting a "hostile takeover" of the party.
Trump is leading in surveys in at least eight of the 11 Super Tuesday states and a CNN/ORC poll showed he was extending his lead nationally with 49 percent support, ahead of Rubio at 16 percent and Cruz with 15 percent. After the top three, retired neurosurgeon Ben Carson has 10 percent and Ohio Governor John Kasich 6 percent backing, according to the poll.
Republican primaries and caucuses are being held on Tuesday in Alabama, Alaska, Arkansas, Colorado, Georgia, Massachusetts, Minnesota, Oklahoma, Tennessee, Texas, Vermont and Virginia.
jm/kms (Reuters, AP)