Anthony Zurcher
BBC North America reporter

Image source, GE

There's no disputing this was a very big night for the Republican front-runner. Yes, he lost Ohio to John Kasich - but he posted easy wins in Florida, North Carolina and even Illinois. He's also in a neck-and-neck race with Ted Cruz in Missouri. 

Depending on how those Illinois and Missouri vote totals turn out, Mr Trump could be in a position to need only 54% of delegates in remaining states to lock up the nomination before the Republican National Convention in July.

The Ohio loss was a blow, but few expected the New Yorker to do so well in the two other mid-west states.

He's not exactly on a glide path to the nomination, but with more winner-take-all states on the horizon, victory is an achievable goal.

That's key because the anti-Trump Republicans are already formulating strategies for challenging Mr Trump in Cleveland if he shows signs of weakness between now and then.

Hillary Clinton capped off a big night with a victory speech, but not everyone was impressed. Echoing earlier comments about the Democratic candidate's tone of voice, some journalists thought she came off harsh. Mrs Clinton's supporters point to these comments as an example of sexism and the double standards she is held to. They say her opponent Bernie Sanders doesn't shy away from raising his voice during rallies, but he is rarely criticised for it.

Mrs Clinton's supporters pushed back against the shouting narrative:

Image source, Getty Images

Bernie Sanders had a less than stellar night on Tuesday, but the Democratic candidate's campaign is staying upbeat, saying coming contests favour the Vermont Senator. He wrote in an email:

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.

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.

Five more states have voted for the party nominees, in a night considered by many as a turning point in the race for the White House.

Stakes were particularly high for Republican candidates John Kasich and Marco Rubio, with both hoping to win delegates from their home states.

So in this unpredictable election, who won and lost in the latest round in the battle for the nomination?

Click here for complete results.  

Image source, AP

In another twist in this unpredictable election cycle, CNBC is reporting, external that House Speaker Paul Ryan won't rule out accepting the Republican nomination for president if the party holds a brokered or contested convention. A contested convention would take place if no candidate reaches the required threshold of delegates (1,237).

"People say, 'What about the contested convention?' I say, well, there are a lot of people running for president. We'll see. Who knows,"  he told the business news channel.

After his win in Ohio, John Kasich is signalling that he may pursue the nomination through a brokered convention. Politico , externalreported on Tuesday that Mr Kasich had hired four advisers who are experts in these conventions.The BBC's Rajini Vaidyanathan and Anthony Zurcher explain the concept of brokered or contested Republican convention using the children's boardgame Hungry Hungry Hippos.

Most US networks are holding off on calling winners in the state of Missouri. At last count, Hillary Clinton held a very slim lead over Bernie Sanders. On the Republican side, Donald Trump and Ted Cruz are also locked in a tight race. Click here for complete results.

Rajini Vaidyanathan
BBC News

Image source, Reuters

“Tonight was a good night,” said Ted Cruz as he addressed a crowd of his faithful who'd packed into a hotel ballroom in his home city of Houston, Texas.

His campaign had entered this second Super Tuesday with relatively low expectations - there were no realistic hopes of winning a delegate-rich 'winner takes all' state like Florida or Ohio - the plan was to pick up delegates where they could, however modest, to add to the tally and solidify their second place to Donald Trump.

But the big prize for team Cruz was Marco Rubio's exit from the race. On stage Senator Cruz paid tribute to his “friend and colleague who ran an optimistic campaign," at the same time appealing to Mr Rubio's supporters to back him now.

The narrowing of the Republican field will delight the Cruz camp who have long argued that the Texas Senator is the only candidate who can beat Donald Trump, and that a wider pool of hopefuls is splitting the vote, and the party. 

But this isn't yet a two horse race. The staying power of Governor John Kasich of Ohio is a residual frustration for Mr Cruz’s ambitions.

Only one candidate has beaten Donald Trump in this race, exclaimed Senator Cruz from the stage as his supporters looked on adoringly,  "not once, not twice but nine times," he said. 

But he failed to mention how many times Mr Trump has beaten him – and therein lies his problem.

Jessica Lussenhop
BBC News Magazine

Image source, AP

In a huge victory for the Black Lives Matter movement and activists in Chicago, the highly criticised Cook County State's Attorney Anita Alvarez has lost her re-election bid. 

Ms  Alvarez faced scathing criticism for waiting over a year to file murder charges against the Chicago police officer who shot an unarmed teenager 16 times. Ms Alvarez did so only after a judge ordered camera footage of the incident to become public. Chicago Mayor Rahm Emanuel dismissed his police chief over the death of 17-year-old Laquan McDonald, but both Ms Alvarez and Mr Emanuel vowed to stay in office. On Tuesday, Cook County voters rejected Ms Alvarez's leadership and proved that the activist movement there has real political clout.

Read more about the Laquan McDonald case

"What is a superdelegate?" was the #1 top question on Google as polls closed.

The answer? Democrats have something known as "super delegates" - influential party officials meant to act as brake to stop a fringe candidate at odds with the party's platform. Many of these "super delegates" are pledged to Hillary Clinton, but they can switch their allegiance if they see voters embracing another candidate. Republicans also have "super delegates", but they receive less attention because they follow, with few exceptions, the results of their state contests. Complete results for March 15

Kim Ghattas
BBC Correspondent

Image source, Reuters

Hillary Clinton did better than her team expected in number of votes and delegates. For days, her advisers were managing expectations, aside from Florida where they expected a blow out victory. 

Even as exit polls showed she was winning in Ohio, her aides were cautious. They wanted no repeat surprise after Mr Sander’s upset in Michigan last week. Both Mrs Clinton and Mr Sanders saw Ohio as a key state: he needed to win there to pick up more momentum and show he was a viable candidate who could win swing states in a general election. 

Instead it was Mrs Clinton who won Ohio and in her victory in Florida, another swing state, she solidified her grip on the Hispanic vote winning by huge margins, all of this will work to the Democrats’ advantage come November. Mrs Clinton is now effectively the nominee even if her campaign isn't ready to say so outright. 

They are making clear that it is now very hard for Mr Sanders to win but insist it’s not up to them to end the Democratic primary process. It’s unclear when the Vermont senator will call it quits. He will likely try to keep generating the excitement of young voters and work to shape the Democratic agenda, pushing Mrs Clinton further to the left until the convention. Will his supporters still turn up if it’s a futile quest? 

Mrs Clinton will be hoping they’ll start to flock to her out of fear of what they see unfolding on the Republican side. In her victory speech, Mrs Clinton was clearly declaring the start of the general election, naming Trump by name for the first time and calling Democrats to rally around for an election she described as consequential not just for the US but for the world. 

Image source, CNN

Politico reporter Ben Schreckinger, who has been covering the Trump campaign, was denied access to the Trump event on Tuesday and escorted away without explanation, despite having received an email giving me credentials him for the event.

He recently wrote a piece, external outlining concerns about Trump campaign manager Corey Lewandowski's behaviour, after a reporter for conservative US site Breitbart filed a criminal complaint against him for assault. 

Mr Lewandowski stood by Mr Trump's side on Tuesday as the Republican front-runner called reporters "disgusting" and did not take any questions, despite billing the event as a news conference.

Politico joins, external numerous other media organisations that have been denied access to Trump events, including: The Des Moines Register, Univision, Fusion, The Huffington Post and BuzzFeed.

Ted Cruz, speaking to supporters in Texas, offered some kind words to Marco Rubio and that his campaign would welcome his supporters with "open arms".

"Less government is more freedom," he said. "Higher wages and a better standard of life for all of us... I will not compromise away your religious liberty, and I will not compromise away your Second Amendment right to keep and bear arms."

She said Donald Trump does not represent the Republican party. She said she is supporting Ted Cruz because he's a true constitutional conservative. 

"Now is the time for us to unify behind the one man who can both beat Donald Trump and Hillary Clinton," she said. 

Nick Bryant
BBC Correspondent

Image source, Reuters

Senator Marco Rubio was once portrayed as the saviour of the Republican Party. He's a Cuban-American supposedly with broad multi-racial appeal. A devastatingly articulate forty-something who could halt what’s been called the GOP’s demographic death spiral, its failure to attract the support of ever more important Latino voters.

But Mr Rubio was an establishment favourite in an anti-establishment year and ran on a hopeful and optimistic message at a time of resentment and rage. Even his story of immigrant success – he’s the son of a bartender and maid, and personifies the American dream – sounded off-key at a time in the conservative movement when anti-immigrant sentiments resonate more strongly. 

Despite hoping that his youth would be a prime asset – he claimed the represent the children of the Reagan revolution -  he’s found it hard to shake off the taunt from Donald Trump that’s he’s “Little Marco,” a political bantamweight not ready to be president. And once he tried to demonstrate his toughness by wrestling with Mr Trump in the mud, trading personal insults above the size of hands and the dimensions of other bodily parts, it was all over. 

Jon Sopel
BBC North America Editor

Image source, Reuters

And then there were three. After Senator Marco Rubio's crushing defeat in his home state of Florida at the hands of Donald Trump, he had little option but to end his campaign for the presidency. At the Mar-a-Lago, Donald Trump's sumptuous gilded palace-cum-private members' club in Palm Beach, this was cause for big celebration.

He didn't just win. He won big. And he won in three other states too. But perhaps unusually - even uniquely - for a man who has totally dictated the media narrative since he convulsed the Republican race by entering the fray last June, the focus might just be on the state that he lost, rather than the state he won.  For John Kasich's victory means that the battle for the Republican nomination not only goes on, it could go all the way to the convention in July. 

And in the Donald J Trump ballroom (what else was it going to be called?) Mr Trump gave a victory speech that sounded anything but victorious. It was low key, understated - and he had the air of a man who was weary of the punishing campaign schedule. Two weeks ago, he seemed much more confident of winning the Republican nomination than he did tonight. 

And tellingly, while he was magnanimous in victory by praising Marco Rubio for running a tough campaign and talking about his bright future, Governor Kasich didn't get a single mention. As if his defeat in Ohio hadn't happened. Maybe it was an oversight - or maybe that the Teflon man has found politics suddenly getting a lot more sticky.