A lot of adults in the US simply cannot register to vote or can’t take time off of work or childcare to do it – and their absence will affect this election

In Belgium’s most recent election, 87% of the voting-age population turned out. In Turkey 84% voted and in South Korea it was 80%. But in the US, in 2012, just 54% of the voting-age population exercised their right to vote. That is one of the lowest turnouts in any developed country.

In fact, this oft-cited statistic is much lazier than the Americans at whom it points the finger. Turnout is more complicated than that.

If instead of looking at Americans over 18 that vote you consider the share of registered voters who show up on election day, the US jumps from 30th place among 34 developed countries to sixth.

There is a simple reason for this: a lot of adults in the US simply cannot register to vote. And their absence will affect this presidential election.

Facebook Twitter Pinterest Turnout in developed countries. Photograph: Pew Research Center

Can’t vote

Take the residents of the permanent US territories – Puerto Rico, Guam, Northern Mariana Islands, the US Virgin Islands and American Samoa. They can work, pay taxes and serve on juries and in the military. But they can’t vote in a presidential election. There are more than four million of them, more than 98% of them from racial or ethnic minorities.

Then there are the estimated 6.1 million Americans who are disenfranchised by state felony laws: about one in every 40 US adults. Racial disparities in the criminal justice system mean that, yet again, a large percentage of those adults are not white. In four states, more than one in five African Americans is not allowed to vote for this reason: Florida (21%), Kentucky (26%), Tennessee (21%) and Virginia (22%).

Then, roughly one in 10 adults in the US doesn’t have a government-issued photo ID. As of August 2016, 31 states enforced voter ID requirements that stop many such adults from voting. According to a report by the Government Accountability Office, ID laws disproportionately affect black and younger voters.

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Finally, there are several non-legal obstacles that stop millions of Americans from voting. The US Census Bureau asks adults why they didn’t vote – the reasons from November 2012 are diverse. They include illness or disability (14%), registration problems (6%) and transportation problems (3%).

A reason given by 19% of non-voters is often treated with an eye-roll, as if it’s always an excuse: “too busy, conflicting schedule”. But for the millions of Americans who can’t arrange childcare or work in jobs where clocking off for a few hours on a Tuesday isn’t an option, that answer is not an excuse, it’s a reality.

The overall effect of all these barriers is that minorities and poorer Americans, people who are more likely to identify as Democrat, are less likely to vote. These facts will negatively affect Hillary Clinton on 8 November, as they have affected Democratic candidates before her.

Won’t vote

Census Bureau data does point to millions of Americans who chose not to vote in the last presidential election. The bureau estimates that 16% of the 19.1 million Americans who didn’t vote were “not interested”, and another 13% felt they “did not like candidates or campaign issues”.

Those reasons are more crucial than ever in an election with the two most unpopular candidates in decades. In national polling averages, there are still only five percentage points that keep Clinton ahead of Donald Trump. The campaign teams will be wondering whether Americans will hold their noses and show up to vote. And, more importantly, if they do, whether they’ll be more likely to choose Clinton or Trump.

Unpopularity ratings Unpopularity ratings

Polling offers some clues. Last week, George Washington University released the results of a survey of 1,000 adults who said they were registered and likely to vote. Only 29% of those who said that they would vote for Clinton said their vote was intended to stop Trump from getting to the White House. By contrast, 43% of Trump voters said their decision was a defensive vote against Clinton.

That doesn’t necessarily get us any closer to forecasting the results. It’s a fact that voter turnout will shape this election outcome but it’s much harder to predict how human nature might affect that turnout. What drives people to action more – support for a set of values or fear of the alternatives? Love or hate?