Super Tuesday 3: What to watch

Updated 11:07 AM EDT, Tue March 15, 2016
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(CNN) —  

If Republicans are going to slow Donald Trump’s march to the nomination, Tuesday’s contests could be their last chance to do so at the ballot box, rather than in a contested convention.

And if Bernie Sanders is going to catch Hillary Clinton’s Democratic delegate lead, he’ll need to pass a big test in Midwestern battleground states.

Your guide to Super Tuesday 3

Voters go to the polls in Florida, Illinois, Missouri, North Carolina and Ohio on Tuesday. Here’s what to watch in those contests:

Can Trump keep rolling?

Once again, Trump has dominated the discussion headed into a big election day – with news cycles in the closing days before the third straight Super Tuesday focused on violence at his campaign rallies. He canceled one in Chicago amid security fears; he said he would look into paying the legal fees of a supporter who is charged with sucker-punching a protestor in North Carolina; he called for protesters who demonstrate at his rallies to be arrested.

Trump has so far managed to avoid any damage from the controversies that have engulfed his campaign from the start. But Tuesday provides another test – with states like Ohio threatening to chip away at his inevitability as the GOP nominee.

Trump wavers on paying legal fees for violent supporters

It’s telling for Republicans who are dead-set on stopping Trump that their hopes Tuesday are resting with two candidates in Florida Sen. Marco Rubio and Ohio Gov. John Kasich who haven’t shown much ability to win contests.

That demonstrates the race’s evolution: Instead of promoting one of the other candidates, it’s all about keeping Trump from amassing the 1,237 delegates he needs to win the party’s nomination outright.

But polls show Trump either ahead or within striking distance in all five states – and a clean sweep could make it next to impossible for any of his rivals, even Cruz, to catch his delegate number by the convention.

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If he wins them all, Republicans will be down to a last hope of somehow denying Trump the delegates he needs and driving the race into Cleveland in a contested convention.