I write these lines from the United States, where the public drama of the election campaign still has over three months to run. But the real election drama has been fought behind the scenes – and it may already have decided the next President. The UK should heed the lessons while we can.

For over a decade, the two main parties have fought a bitter partisan war over voter registration. At the risk of simplification, the Democrats have been trying to get voters on the ballot, especially among the groups most likely to vote for them, and the Republicans have been trying to keep them off. The Democrats did especially well among the 18 million or so new voters who registered between 2004 and 2008: an estimated two thirds of them chose Barack Obama. This year the Republicans are determined to prevent a repeat.

In 20 crucial swing states Republican governors and legislators have made strong efforts to keep voters off the ballot. They have been marshalled by a well-organized lobby, the American Legislative Exchange Council, funded by the ultra-rich, ultra-conservative and ultra-secretive Koch brothers. Their prime targets are poor people, African-Americans, Hispanics, students and young people generally, and voters born outside the United States – all groups more likely to vote Democratic. One Republican legislator, Mike Tuzai of Pennsylvania, admitted openly that his party’s tough new voter identification laws were designed to deliver the state and its 20 electoral votes to Mitt Romney.

The Republicans have used four methods. One is to introduce new restrictions on volunteer organizations which conduct voter registration drives. The highly respected, non-partisan League of Women Voters has 70 years’ experience of registering new voters. The Michigan legislature decided that their volunteers required prior state training, although state training courses were non-existent.

Two crucial battleground states, Florida and Ohio, clamped down on early voting, especially on the Sunday before election day, long used by African-American churches to get their congregations to vote after attending services.

Five key states, again including Florida, introduced new measures to purge or exclude former felons (the tactic which delivered Florida – and the United States with it - to George W Bush in 2000).

However, the crucial Republican tactic has been to introduce stiff new demands for photo-identification for voters. As many as fifteen key states have done this. Their rationale is the prevention of voter fraud, although in reality this is extremely scarce. George W Bush’s Justice Department hunted for cases from 2002 to 2007 and found only one to prosecute.

Republican measures target the 11 per cent of Americans who do not have the standard form of photo-ID, a driver’s licence. They tend to be young, or poor, or non-white, and to obtain alternative photo-ID they are often forced to travel to remote state offices with limited opening hours, and to pay large fees. The Republicans have also made it hard or impossible to use a student ID to vote. In Wisconsin they attached conditions to this which no Wisconsin college can meet. Texas bars the use of student ID for voter registration, but allows the use of a concealed-gun permit.

Some Republican states, including Florida and Pennsylvania, face legal challenges to parts of their measures, but the great majority are likely to stay in place in the run-up to the election. On election day itself, poor and non-white voters in Republican-held states will almost certainly find it harder to get to their voting stations than affluent white ones – a factor which helped George W Bush take the vital state of Ohio in 2004.

This month the Brennan Center for Justice produced a study of the likely impact of the most restrictive voter ID laws in the ten states concerned. It confirmed that poor and non-white voters were less likely to hold photo-ID than the general population, and revealed that 1.2 million eligible black voters and 500,000 Hispanic voters lived more than 10 miles away from their nearest full-time ID issuing office. It also found poor people likely to be deterred by charges of up to $25 for a birth certificate or a marriage license. It noted that the ten states concerned provide 127 votes towards the 270 needed to win the Presidency and concluded “the ability of eligible citizens without photo ID to obtain one could have a major influence on the outcome of the 2012 election.”

To put it more bluntly, the Republicans could win the election and introduce a fiercely partisan programme afterwards by denying millions of potential victims of that programme their right to vote against it. No friend of the US could think that a good outcome. These are the methods of Vladimir Putin, not the leader of the free world.

However, we in Britain have no right to lecture the Americans about electoral process and voter registration. The Parliamentary boundary changes would remove 20 non-Conservative seats before a single vote is cast, and changes in the powers of returning officers have led to the disqualification of thousands of votes on election night. However, the greatest worry is that our next general election could see additional millions of voters excluded from the already incomplete register. This would not be the result of partisan manoeuvring, but the unintended consequence of the government’s introduction of individual voter registration.

The House of Commons select committee studied this issue in depth last year. We received powerful evidence about the extent of under-registration not least from the impartial Election Commission and the Association of Returning Officers, who said up to a third of electors could be deregistered. Other authorities believe that as many as six million eligible voters may not be registered, rather than the 3.5 million normally cited. The non-registered are most commonly poorer people, especially the unemployed and those on the minimum wage, inner-city residents, especially in rented housing, and people from minority ethnic or language communities.

Individual registration could make this problem even worse and the select committee recommended a range of changes to prevent this, including a penalty for non-registration combined with a major public information and outreach effort directed at the groups least likely to register. We have the opportunity to get this right since the Bill is still before Parliament.

Without such measures, our country could follow the US into electing an illegitimate government from an unrepresentative democracy.

Graham Allen is Labour MP for Nottingham North.