Hillary Clinton
Democratic presidential candidate former Secretary of State Hillary Clinton speaks to her supporters during her Primary Night Event at the Palm Beach County Convention Center on March 15, 2016 in West Palm Beach, Florida. Getty Images

The five states participating in the Mega Tuesday primaries on 15 March proved to be election-changing, with a Republican candidate dropping his presidential bid and one state too close to call. Democratic frontrunner Hillary Clinton swept to victory across four states, while Republican frontrunner Donald Trump took wins in three states, and Ohio Governor John Kasich clinched a victory in his home state.

The biggest game-changer on the GOP side was Florida Senator Marco Rubio's decision to drop out of the race following a devastating loss in his home state. While Rubio's supporters mourned his departure, Trump's supporters cheered his key victory in the Sunshine State. As a winner-take-all state, Florida's 99 delegates were awarded to Trump.

In the other winner-take-all state of Ohio, Kasich soundly defeated Trump, marking his first state victory. The popular Ohio governor took home all 66 of the state's delegates and gained the momentum to continue his campaign until the next Republican primaries on 21 March.

Despite his loss in Ohio, Trump managed several wins on Super Tuesday 3, with wins in Illinois and North Carolina. The night's wins further his delegate count and placed him one step closer to winning the party's nomination. Texas Senator Ted Cruz failed to win in any state, but with nearly 400 delegates, he continues to be the biggest threat to Trump's presidential ambitions.

On the Democratic side, Hillary Clinton clinched clear victories in four of the five states. Clinton's victories, including the unexpected wins in Illinois and Ohio, put her one major step closer to closing in on the Democratic nomination.

Clinton currently has a total of 1,096 pledged delegates (with an additional 472 super delegates, who are ultimately free to vote at the convention the way they choose). Sanders has 774 pledged delegates, with an additional 23 super delegates. To win the nomination a candidate needs 2,383 delegates.

Sanders, who campaigned hard in all five states and outspent Clinton, acknowledged her success but vowed to remain in the running for the nomination until the party's convention in July. "I congratulate Secretary Clinton on her victories on Tuesday. I also want to thank the millions of voters across the nation who supported our campaign and elected delegates who will take us all the way to the Democratic National Convention in Philadelphia," he wrote in a statement to the press.

"With more than half the delegates yet to be chosen and a calendar that favours us in the weeks and months to come, we remain confident that our campaign is on a path to win the nomination," he added. Sanders could still manage to eke out a win in Missouri, although that is highly unlikely. The race in the Show-Me State was too close to tell, although Clinton was in the lead. Likewise, the GOP race in Missouri had Trump barely ahead of Cruz, but still too close to call.