The United States midterm elections happening on Tuesday (US time) are perceived by some as a referendum on President Donald Trump.
US political expert Maria Armoudian says it's an important time in the country's history.
"The United States is at a point I would call a crisis at the moment," she told The AM Show. "I think democracy itself is at stake."
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Polling is closing at around 8pm in most areas on November 6 in the United States. That means results will be coming in through the afternoon on Wednesday in New Zealand.
Control of Congress is up for grabs in the polls, and the President's ability to govern in the final two years of his term will heavily depend on the outcome of the votes for all 435 seats in the House, and 35 of the 100 Senate seats.
The United States' midterm elections are held in November every four years, two years either side of the general election, hence the name 'midterm'. Members of the US House of Representatives are only elected to two-year terms, so all 435 seats in the House are up for play.
Americans will also be voting on members of the US Senate. A senator's term in office is six years, so every election (be it general or midterm) roughly one-third of the seats in the US Senate come up for grabs.
This year, 33 seats are up for grabs, with two more being contested in special elections, bringing the total to 35. On top of that, 36 US states will vote to elect a new governor in the midterm elections.
With a Republican majority in the Senate and House, as well as a Republican in the White House, it's been fairly plain sailing so far as approving new legislation for the Trump administration.
However, if the Democrats can win a majority in either, or both, of the chambers of Congress (the House of Representatives and the Senate) they'll be able to drastically affect Mr Trump's ability to govern by blocking new legislation when it's passed through Congress.
"Should there not be a flip in power in one of the Houses, to not have a divided government, to not have some checks and balances on power, then you might see a further following away of the US from democracy," said Ms Armoudian.
"If you don't have the majority in either House, you have absolutely no power in the US Congress."
The House is the one that brings forth articles of impeachment, so should Democrats get the House, there is a chance Mr Trump's impeachment could be called for.
The midterm elections are being held amid a wave of violence, including mail bombs sent to prominent Donald Trump critics and a deadly attack at a Pennsylvania synagogue. Tensions are running high, with race-baiting allegations miring the homestretch.
To rally support for Republicans, Mr Trump has held campaign rallies nationwide, even though he is not up for election this year. He's warned his supporters against "socialism" and "an invasion" of migrants travelling from the Central American caravan - which some have called "racist".
Mexico has said 2800 to 3000 people are in the caravan, Reuters reports, which left Honduras in mid-October, although many are expected to drop off before reaching the US border.
US TV networks CNN, NBC and Fox News announced on Monday they would halt the broadcast of a 30-second ad paid for by the Trump campaign. It falsely claimed Democrats let an undocumented Mexican into the US who murdered two Californian sheriff's deputies in 2014, BBC reports.
The US states of Florida and Georgia have been mired by racist political campaigns to undermine two candidates who could become the first African-American governors of those states.
An automated phone call claiming to be from US celebrity Oprah Winfrey calls Georgia candidate Stacey Abrams "a poor man's Aunt Jemima", referencing a controversial black woman stereotype from the slavery-era known as "mammy".
The Associated Press reported last month that 53,000 voter registrations - 70 percent of them from black applicants - were being held by then office of Ms Abram's opponent, Brian Kemp, for failing to meet registration information - an apparent move to block their votes.
No other US general election in the last decade has seen close to so much controversy and so many attack ads as the current midterms, according to the Wesleyan Media Project.
"With control of Congress up for grabs and more competitive races, we generally expect campaign activity and negativity to increase," said co-director Erika Franklin Fowler.
"But the amount of negative ads - and sheer amount of advertising on television more generally in 2018 - is really stunning."
Analysts say there's been a sharp rise in turnout this year for the midterm elections, and Democrats are expected to get the seats they need to take over the House of Representatives.
But they are expected to fall short of taking control of the Senate.