From the first day of her candidacy, the first lady was the most polarising figure in the race.
Her political beliefs and public statements have often been criticised.
How has she changed?
She has been seen as a liberal who is not beholden to Washington or the establishment, and as someone who would not go down the path of the US president.
She has said that if she is elected she will use her position to change things for the better, like the US Senate.
What did she say?
During a town hall meeting in Florida in October she talked about her support for a plan that would allow the US to withdraw from the Paris climate agreement.
She also said that the US was being held hostage by global warming and that there should be a ban on fracking.
What is the scientific evidence for her views?
The Trump administration has been sceptical about global warming.
In November it issued a report saying the US has the worst record on global warming in the world.
But it also said global temperatures have been on the rise for decades, even as the number of US jobs has risen.
It also said the country could have a very serious climate problem.
She is a staunch climate sceptic.
What about other candidates?
The Democratic frontrunner, former Maryland governor Martin O’Malley, said during the presidential debate that global warming was “just a theory” and that he believed it was a hoax invented by the Chinese.
He was challenged by his Republican opponent, former Texas governor Rick Perry, on the issue during the Republican debate.
The former governor did not directly address the issue, but he said that it was the “perfect example of the way you would have a president of the United States saying, ‘We are going to be the one that takes care of it, we are going, you know, we will have a new way of doing it’.” What does it mean for the presidential race?
The race between Hillary Clinton and Bernie Sanders has been a close one, with Clinton winning about 40% of the vote to Sanders’ 42%.
But with only a month to go before the first ballot is cast, there are some questions that are still unanswered.
How important is this race for Democrats?
Clinton and Sanders have both spent the past month and a half campaigning.
Both candidates have made large donations to Democratic groups.
Sanders has also had to fight for endorsements from several key Democrats.
What do Democrats think of the candidates?
They have had mixed reactions to the two, with some suggesting that it could be a good thing to see both candidates face off in the same race.
In an interview with CNN’s State of the Union, former vice president Joe Biden said that this is a great opportunity for the Democratic Party.
“You know, when you look at who is in the White House, this is the best opportunity for us to be in the Oval Office.
And so that is what this is all about.
It is about having a voice in the presidency,” he said.