After the polling irregularities in Florida in the 2000 Presidential election, which saw George W. Bush come to office, David Earnhart did nothing. But when it was repeated in 2004, he could not let it pass again.

“A lot of people were angry in 2004,” Mr. Earnhart said this week from his office in Nashville. “But where most everybody else moved on, I didn’t.”

He stayed with it for three years, trying to work out what had gone wrong with the American electoral process. The result of his investigations is a documentary film, Uncounted: The New Math of American Elections, which has been playing around the country for the past couple of months and is screening on the Island Saturday as part of the Martha’s Vineyard Film Festival.

It is a truly frightening film, a collation of all the ways people’s basic democratic right to have a say in who governs them has been subverted, by flaws in the system and flaws in the technology.

The old saying is that given a choice between a conspiracy and a foul-up, you should always assume the foul-up. But even if you were to put the most charitable interpretation on most of the evidence compiled in this movie, that the widespread, massively inaccurate vote tabulation was due to error of one kind or another, it would still be utterly unacceptable.

Electronic voting machines that leave no auditable paper trail, with inadequate security systems built in to the technology, for example, could be just the result of poor design and cost-cutting by the firms that make them.

Alas, though, Uncounted encourages a much darker view: that much of it was deliberate. That people, mostly people aligned with the Republican Party, set out to steal elections.

The evidence is powerful, if mostly circumstantial — the links between voting machine companies and the party, the disappearance of the names of likely Democrat voters from the rolls, the persecution of whistle blowers who point out the defects in the machinery of voting, the extraordinary disparities between precincts in the numbers of invalid votes, the vast disparities between machine-recorded votes and paper ballots within electorate and between exit polls and official counts, the reluctance of authorities to accept technologies that would make voting machines harder to tamper with or produce a paper record of every vote cast.

But there is direct evidence, too, of manipulation. There is, for example the testimony of the computer technician who swears he was asked to produce a program which would “flip” votes from one party to the other, and his demonstration of how he did it.

Whether you adopt the conspiracy theory or the foul-up theory, the evidence of major problems in exercise of U.S. democracy that Mr. Earnhart and his team have gathered is overwhelming.

It was the Ohio result in 2004 which started him investigating, with good reason.

“Ohio was the Florida of 2004,” said the filmmaker. “You had more than 350,000 people who were prevented from voting, and the vast majority of these were Democrats. You ended up with these long lines, particularly in African-American precincts, of people waiting two hours, three hours, five hours and in one case 15 hours to vote. People couldn’t wait, they had to get to their jobs or home to their kids.

“I just thought that if your vote doesn’t count, it sort of swamps all the other issues. It’s kind of at the core of who we are meant to be as a democracy. It’s so difficult to get other issues solved if people don’t have a voice,” he said.

And so Mr. Earnhart, who owns a video production company which previously had worked mostly on making presentations for clients — nonprofit groups, colleges, that sort of thing — decided to make a movie. “I had never done a full-length documentary before,” he said.

But it’s more than a documentary. It is also a Web site, with links to sources and activist organizations. It gives people advice on how to get involved in reclaiming the electoral process — to take a camera when you go to vote in case there are problems, to ask for a paper ballot, how to lobby politicians to fix the system.

And Mr. Earnhart’s activities since the film’s launch have been less like a publicity tour than like a rolling political campaign.

“We started on a national tour in mid January. What we’re doing is threefold. I’m going out with the film, going to theatres, introducing it, hooking up with local organizations that might be doing work on this issue. After screenings, we have a discussion. Sometimes it’s just me. Sometimes it’s also a couple of other people that are working on local issues in that particular area,” he said.

“We’re also keeping in touch with a couple of organizations across the country, doing what I call house parties, showings by community groups or individuals. One night we had 200 showings organized in 42 states across the country. They were organized by Democracy For America, which is Jim Dean’s [former Presidential candidate Howard Dean’s brother] organization. At the end we did a conference call with them all.

“The other bit of it is when people go to this film, they really want to share it with others. Pretty typically, if we have a couple of hundred people there, they’ll walk away with 70 or 80 DVDs.

“People want to get involved. It’s been pretty gratifying, what’s happening,” he said.

And notwithstanding the fact that problems with the vote count continue — large numbers of votes, mostly again for Democrats, went uncounted in the 2006 midterm elections, and there have been problems even in the current presidential primaries — Mr. Earnhart said he is buoyed by signs of change.

“The biggest thing personally is that when I started doing this documentary and I would tell people about it, there wasn’t much recognition of what I was really talking about.

“And now when I tell people about the documentary, they get it. They say ‘Oh, that’s important. I’ve been worried about that.’

“The media have started to talk about this story in a way that they weren’t before. The Intenet, bloggers, political studies and computer scientists...”

Even better, no less authority than the Government Accountability Office has determined that many of the concerns about the poor security, frequent malfunction and potential corruption of electronic voting machines were justified.

And most important of all, he said, is that a large number of states are enacting legislation requiring that voting machines also issue a paper ballot that can be audited.

But the fight is far from over. Indeed, said Mr. Earnhart, it can never really be over, for electoral manipulation is as old as elections.

“This is not about trying to get a different party in office, this is about the 2008 election being run fairly and honestly,” he said.

“The reality of what’s happened in recent years has been primarily a matter of where the problems have worked against the Democratic Party, but I think that’s mostly of a reflection of the recent era [of Republican dominance] that we’ve been in,” he said.

“History shows that whoever’s in power has the greatest opportunity to manipulate the system. But now the stakes are much, much higher because it’s so much easier to manipulate.

“In the past you had to change things ballot box by ballot box. The technology of computer voting allows massive vote shifting in a way that is just unprecedented in our history. It’s a scary situation.”

Uncounted screens Saturday at 12:45 p.m. at the Chilmark Community Center. Children’s films will be shown free at the same time at the Chilmark Public Library.