Pivotal 'Super Tuesday' could elevate Trump, Clinton

Americans vote Tuesday in what is deemed the most pivotal day in the presidential nominating process, with front-runners Hillary Clinton and Donald Trump hoping to finish off their challengers.

Voters in a dozen states will take part in "Super Tuesday" -- a series of primaries and caucuses in a dozen states ranging from Alaska to Virginia.
 
If Democrat Clinton and Republican Trump -- an outspoken billionaire political neophyte who has unexpectedly tapped into a reservoir of conservative rage at conventional politics -- win big, it could spell doom for their challengers.
 
With just hours to go before polls open, the duo made last-ditch appeals to supporters ahead of a day like few others on the calendar leading to the November election for the White House.
 
Trump's Republican rivals, Senators Marco Rubio and Ted Cruz, were trying frantically to halt the real estate magnate's march toward the nomination, seeking to unite the party against the man they see as a non-conservative political interloper.
 
Clinton meanwhile was riding high after thrashing rival Bernie Sanders in South Carolina over the weekend, securing an astronomical 86 percent of the African-American vote in her third win in four contests.
 
Should she win black voters by similar margins in places like Alabama, Georgia and Virginia, she should dominate there to become once again the inevitable candidate.
 
That was her status at the start of the campaign -- before the rise of Sanders, a self-described democratic socialist.
 
She was leaving nothing to chance, traveling to multiple states on Feb. 29 to urge a strong turnout.
 
Clinton also took aim at the increasingly hostile campaign rhetoric on the Republican side...