Update on the U.S election

Donald Trump has been greeted with a hail of boos near his New York home as he cast his vote in an historic US election against Hillary Clinton.

He arrived at the polling station with a motorcade of limousines at a school in midtown Manhattan where he was peppered with shouts of "New York hates you" from hundreds of voters outside.

Controversy continued to follow the Republican nominee on election day when he told Fox News he may not accept today's result.
"We’re going to see how things play out," he said when asked if he will challenge polling results.

And his campaign have already launched a lawsuit against a Clark County registrar in Nevada for reportedly keeping a polling booth running two hours longer than scheduled.
Lawyers claim the act was an attempt to benefit Democrat voters.

Hours earlier, about 150 supporters chanting "Madam President" gathered as Clinton was joined by her husband Bill as she voted at an elementary school near their home in Chappaqua in New York state.
 "I'm so happy, I'm just incredibly happy," said a smiling Clinton as she emerged from the polling station, shaking hands, mingling and chatting with the crowd.

"All my friends and my neighbours, it makes me so happy."

Clinton told reporters after casting her ballot that it was "the most humbling feeling" to vote for herself for the nation's highest office.
"I know how much responsibility goes with this and so many people are counting on the outcome of this election, what it means for our country," she added.

"And I will do the very best I can if I'm fortunate enough to win today."

Clinton has enjoyed a bounce in her poll standing in recent days and leads her Republican rival by 3.3 points nationally in the rolling RealClearPolitics poll average
Later today, the former secretary of state heads to the Javits Convention Center in New York, where her team holds its final election gathering.

Voting is now open in all states.

At midnight local time on Tuesday, the residents of tiny Dixville Notch in New Hampshire cast their traditional first-in-the-nation ballots with a total of eight votes — four going to Clinton and two to Trump.

When will we know the result?

From 10am AEDT onwards, the first ballot count will begin and we'll start to get an idea of who's going to be the next president.

Some states will be called straight away, thanks to the media's use of exit polls.
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Nine political editor Laurie Oakes and TODAY'S Karl Stefanovic are in New York on election eve.

Exit polling is the process of quizzing people as they leave voting stations to ask who they voted for. It's just a batch of people with clipboards, but when there's enough of them, it's possible to judge who's in a winning position.

So if a candidate is in a clearly dominant position in exit polling, networks and news channels in the US will be comfortable calling a state the moment polls close. There's nothing stopping them from calling them earlier, but a sense of collective propriety and caution stops them doing so.

If this year is going to be anything like the last few elections, the first state declared will be a Trump one. Kentucky is the first state to close all its polls, and it has become a solid Republican state in recent decades.

From there we'll get a real sense of how the election is panning out when polls close in Florida, North Carolina and Ohio. If Donald Trump can't win all three of them, his path to the White House is nearly impossible.
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The bottom line is, it's a race, and the target is 270 electoral college votes.

Despite that, we won't have a confirmed result for a few more hours. While the western states like California and Washington are seen as foregone conclusions, it may be necessary to wait until polls close there until a call can be made. If it takes about the same amount of time as last election, we should have a winner by 3pm AEDT.

What is the electoral college?

Rather than award the presidency to the person with the most votes, the United States runs on the more complicated electoral college system.

Each state is apportioned a certain number of electoral college votes based on its population. California has the most with 55. Wyoming, the Dakotas, Montana, Alaska and Vermont have three each. If you win the state, you win all of their electoral college votes. And the candidate to accumulate 270 electoral college votes wins the presidency. Needlessly complicated, right?

Despite being behind in the polls, Donald Trump isn't going down without a fight.

The system allows for swing states to have an outsized influence in the election. If a state is considered a given for either candidate, neither candidate will campaign there. But if a state is up for grabs, they will be there constantly.

What are the swing states?

There are a few states to look out for when the results start coming in. This year the election hinges on Florida, North Carolina, Iowa, Ohio and Pennsylvania. Trump has proven unusually strong among non-college educated white voters, which is what puts him in a strong position in Ohio and Iowa. But his weaknesses with college educated whites, black voters and Latino voters is putting him behind in Florida, as well as states like Virginia, Colorado and Nevada.

What gives Clinton the edge is the changing nature of the American electorate. In 2012 Barack Obama won the same proportion of white voters, black voters and Hispanic voters as George McGovern did in 1972. But McGovern lost 49 states and Obama won. America is nowhere near as white as it used to be, and it has given Democrats the edge in presidential elections.

Who will win the election?

The polls of the last few days have shown Clinton with a narrow edge over Trump. There's always a margin of error in political polls, so Trump definitely has a chance. But nearly all polls show Clinton ahead, and it's unlikely they are all wrong.

So by mid-afternoon Australian time, it's looking likely that glass ceiling will be smashed and Hillary Clinton will become the first female President of the United States.