This story was written by Investigative Producer Pia Malbran.
With Election Day rapidly approaching, a new report, obtained exclusively by CBS News chief investigative correspondent Armen Keteyian, raises serious questions and exposes flaws in the way states maintain their voter registration rolls.
States and counties regularly update their voter registration rolls for accuracy, removing people who have moved, died, or committed a felony. It is known as "voter purging."
But, the new report by the non-partisan public policy and law institute, the Brennan Center for Justice at New York University School of Law provides troubling new insight into the process. There are no national standards and as a result, the cleaning up of voter rolls is not as precise as it should be and eligible voters are often wrongly removed.
The Brennan report calls the nationwide process "chaotic," "shrouded in secrecy", "riddled with inaccuracies", "prone to error" and "vulnerable to manipulation."
"What's wrong with the process is it's happening in secret. It's happening with no accountability," Michael Waldman, the center's executive director, told CBS News.
Waldman also says some voters will show up on Nov. 4 who are supposed to be registered to vote and will be told they are not listed that way. If that happens, he says, "don't take 'no' for an answer. Cast a provisional ballot and call a voter hotline."
The numbers of purges that occurred are hard to uncover and often are not known until after an election. But, the report cites several controversial purges this year so far.
For example, in Muscogee County in Georgia, the report says, a county official purged 700 people from voter lists for criminal convictions. Many of the people who received letters informing them of the purge, however, had never even received a parking ticket. In Mississippi, a local election official recently discovered that another official had wrongly purged 10,000 voters "from her home computer."
The reasons for wrongly purging eligible voters ranges from clerical errors to mistakes in matching names, addresses and criminal histories. Waldman says there's a "huge potential for partisan mischief" and manipulation.
Another study, by the group U.S. PIRG, released last week, also looked at the issue of voter purging and discovered that 19 states are ignoring a federal law banning systematic purges within 90 days of a federal election. The 19 states include battleground states of Colorado, Ohio and Nevada.
As a solution, the Brennan Center recommends that in the future the government implement a nationwide universal voter-registration system.
Waldman said: "when you register once, you stay registered. The government keeps the list. You can prevent fraud. You can prevent people who aren't eligible from voting. But everybody who's eligible gets to vote."
Doing something like this could add up to 50 million more people to the voter rolls every year.
He said: "Every eligible citizen should know that on Election Day they can show up to vote, without worrying whether their name's on the list."
By Pia Malbran