The 2016 Democratic and Republican primaries have already been an astonishing spectacle. Anti-establishment candidates Donald Trump and Bernie Sanders have turned traditional wisdom about what is politically feasible in the US on its head. They have created a situation where the unpredictable is now normal and where candidates who, even recently, looked like unassailable contenders, are having to fight for every last vote.

So, as the most dramatic “Super Tuesday” in recent years arrives, a key group of up to 6m American voters – one that’s been largely overlooked – may end up playing a more important role than ever. American expats have played a critical role in US elections in the past, and 2016 may see them do so again.

We’ve analysed this important constituency in a new report, America’s Overseas Voters: How they could decide the US Presidency in 2016.

On March 1, Democrats Abroad, the expat wing of the Democratic party, will hold its global primary, with polling stations open across the world. Democrats Abroad is recognised as a “state” for primary voting purposes, and will send roughly the same number of delegates to the Democratic National Convention as will smaller states such as Wyoming or Alaska.

Given that the Clinton–Sanders contest has been much tighter than expected and that Sanders has reiterated his intention to run the race to the finish, it’s not unrealistic to imagine that the expat delegates could play an outsize role in the outcome.

The Republican Party doesn’t have the same formal process for expats to send delegates to the party convention, where the presidential candidate will be formally nominated. But Republicans Overseas has been working hard to encourage its members to vote in their home state primaries through absentee ballots.

Political impact

Anyone who’s sceptical about the impact of expat voters needs only to think back to the 2000 presidential election, when overseas ballots provided the push that finally put George W. Bush in the White House. As we write in our report, had that election been decided on the ballots that arrived by the 26 November deadline, Al Gore would have won the state of Florida, and therefore the presidential election, by 202 votes.

Overseas voters also donate large sums of money to presidential candidates. The parties clearly know this: Howard Dean, former presidential candidate and Democratic National Committee chairman, visited London the week before Super Tuesday to raise funds and help get out the expat vote.

While they do not have their own primary or caucus, members of Republicans Overseas were able to register their support for their chosen candidate online. The results of that poll, which included voters from 67 countries, were released at the end of January, and indicated that the Republican electorate around the world is noticeably more moderate than that in the US.

Our report also looks at how the parties’ relationships with overseas US voters relates to the state of each organisation within the US.

Both Democrats Abroad and organisations representing expat Republican voters are ambitious, and they are both working hard to develop exciting and effective ways to represent party members and the wider overseas US community. But Democrats Abroad is much more deeply embedded into the national party structure – which provides that organisation with significant advantages over the Republican organisations operating outside the US.

Its closeness to the Democratic Party in the US and the genuine voting opportunities it provides mean it can more easily generate enthusiasm among expats. In many ways, this difference between a highly organised and outward-looking Democratic party and a more domestically focused and less polished Republican party seems to mirror the domestic party set-ups.

But just as delegates in the Democratic Primaries, and even the Presidential election, overlook the expat vote at their peril, so a charismatic candidate can still undermine all of the best organisation a political party can muster.

Jay Sexton does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond the academic appointment above.

Jay Sexton, Director of the Rothermere American Institute and Fellow in American History, University of Oxford

This article was originally published on The Conversation. Read the original article.