Americans head to polls in critical day of voting

In what is seen by many as the last chance to halt Donald Trump's momentum before the Republican National Convention in July, voters started heading to the polls on Tuesday in Florida, Illinois, Missouri, North Carolina and Ohio.

Tuesday's primaries, dubbed by members of the media as "Super Tuesday 2," are critical for the Republicans, as two of the states - Florida and Ohio - have a winner-take-all system in which the victor will rake in large numbers of delegates needed to win the party's nomination in July.

Another reason why all eyes are on Florida and Ohio: They're the home states of two of Trump's rivals, Marco Rubio and John Kasich, respectively. If Trump wins in Florida - as polls seem to suggest he will - the pressure will mount for Rubio, once seen as the Republican establishment's beacon of hope in an increasingly anti-establishment presidential race, to drop out of the contest. On the other hand, if Kasich wins in his home state of Ohio - where several polls show him holding a slight lead over Trump - it will likely encourage him to stay in the race until July.

Texas senator Ted Cruz, Trump's most successful rival in terms of primary victories, will likely take the fight all the way to the convention as well, even as the billionaire New Yorker is predicted to sweep all of Tuesday's contests save Ohio.

The same day as the primaries, President Barack Obama took aim at the crude tone of the Republican race, and even criticized Trump, albeit implicitly.

"We have heard vulgar and divisive rhetoric aimed at women and minorities, and Americans that don't look like us or pray like us or vote like we do," Obama said at a luncheon on Capitol Hill.

Hillary looks set to extend lead

Democrats will also vote in all five states, where Hillary Clinton maintains a lead over rival Bernie Sanders.

Polls suggest Clinton will win big in Florida and North Carolina, while Sanders has a narrow lead in Missouri. The self-described democratic socialist from Vermont also appears to be closing in on Clinton in Ohio and Illinois.

Last week, Sanders shocked the political establishment by scoring a major upset in another Midwestern state, Michigan, even after a debate performance in which his rival assailed him for opposing government bailouts for the state's deeply rooted automobile industry.

On Monday, Sanders was in Youngstown, Ohio - once a leading producer of steel - where he slammed "disastrous" trade policies before an audience of some 2,000 people.

blc/kms (AP, AFP)