As the United States goes to the polls the country's unique electoral system will once again be on display.
Unlike in most modern democracies, the candidate who wins the most votes does not necessarily win the election. Instead, each of the states is ascribed a certain number of “electoral college votes”.
Candidates must win at least 270 of the total 538 electoral votes available. In a further quirk, the founding fathers of the republic in the late 18th-century decided that electors – and not the American people – would officially cast their ballots for president. These state representatives transmit the result from their state to several institutions in Washington, a process which will occur on December 14th this year.
Within the electoral college system, California has the highest number with 55 votes, while sparsely-populated states like Wyoming and Alaska have the minimum number of three.
As a result, there is little point in candidates campaigning in partisan states – New York is always going to vote Democrat, for example, while Kentucky can be counted on to choose a Republican candidate.
Instead, the focus is on states that traditionally swing between Democrat and Republican and have historically reported tight margins, or states that are changing demographically. An example this year is Texas, where Democrats are hoping that an influx of new voters to suburban areas around the state’s big cities may push the state into the Democratic lane.
States with a high number of electoral college votes – Florida with 29, Pennsylvania with 20 – are obviously more valuable, and traditionally attract significant investment from candidates.
Most states operate a winner-takes-all system – ie, if a candidate wins more than 50 per cent of the vote, he or she is awarded all the electoral college votes for that state.
Vote margin
Trump’s electoral trick last time around was to win a trio of states in the midwest known as the “rust belt” – Michigan, Wisconsin and Pennsylvania – which Democrats had hoped to win. The margins were tight, but it didn’t matter. He scooped up their 46 electoral college votes, and in the end won the election with a healthy 304 electoral college votes compared to Hillary Clinton’s 227.
This year, as in other years, the candidates are working out possible “paths” to victory – states that will help them reach the 270 threshold.
In the vast majority of cases, the candidate who wins the popular vote also wins the electoral college system, but notable exceptions include the 2000 race, which came down to a few hundred disputed votes in Florida, and 2016.
Hillary Clinton won 65.8 million votes, while Donald Trump won 62.9 million, with the result that she won the popular vote by 2.9 million votes – the largest vote margin of any losing presidential candidate in American history.
Four years later it is quite possible that Joe Biden could win the popular vote by an even bigger margin – for example, by racking up huge numbers in coastal states – but still lose the electoral college.