By Ted Mellnik, Reuben Fischer-Baum and Kim Soffen | Washington Post

Thousands of Virginia voters may be registered in the wrong state House district, raising the possibility of election disputes and of votes that don’t count where they should.

In a statewide analysis, The Washington Post found addresses of about 6,000 registered voters that appear to lie outside a map of the assigned House district. If their turnout tracked the state average, more than 2,800 mistaken state House votes could have been cast in November.

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One controversy stemming from such errors is now playing out in the 28th House District near Fredericksburg. Democrats are seeking a new election because 147 people voted in the wrong race, while Republican Bob Thomas won by just 73 votes. (They can’t just throw out the individual bad ballots since they can’t be identified). A state Department of Elections investigation there, launched following voter complaints, found the 147 affected voters got the wrong ballot because official voter registration records placed them in the wrong district.

Local election officials say such mistaken votes can happen because the state’s labor-intensive voter registration system allows incorrect details to be recorded. And errors, once entered, are difficult to detect.

Walter Latham, the York County registrar and president of the Voter Registrars Association of Virginia, says registrars lack resources. “With elections, until there’s a problem, people aren’t worried . . . and it’s not a budget priority.”

When the legislature redraws its districts, the boundaries are built, block by block, with the help of modern computer mapping. But the local registrars, who match voters to those districts, must first manually assign lists of street blocks to districts, sometimes specifying down to the level of one side of a city block, or even a single apartment building.

“It can be very tedious,” said Linda Lindberg, elections director and registrar in Arlington County. Latham said, “It’s about as manual a process as you can use and still be using a computer.”

Many of the registration errors found by the state in the 28th House District originated when districts were redrawn following the last census in 2010, and so had been in place undetected for at least three legislative elections. A lawyer for Democrats protesting the 28th House District election said complaints about registration errors there started two years ago. Still, in the November election, some voters got the wrong ballot because no one had noticed that in the street block list “Charles” and “Charlotte” streets had been mixed up during redistricting.

Cul-de-sacs can also add confusion since they don’t always have “sides” the way other streets do.

Another occasion for errors is new construction, according to Lindberg, the Arlington registrar. Imagine a street split by a district boundary, with homes on the left side of the boundary, but an empty field on the right. Registrars could properly consider this block to be in the left district, since all the homes on the block are in that district. But that means when homes are built on the right side of the boundary, and should be in the right district, they are actually included in the left district.

Michael McDonald and Brian Amos of the University of Florida also found the underlying geography of a district, especially in rural areas, can lead to errors. If a house is set far back from a road but the state geolocates it to be along the street, it could be coded into the wrong district.

Virginia’s lists of voters and street blocks are housed in statewide elections department databases, but Virginia Elections Commissioner Edgardo Cortés said his department has no responsibility to ensure voters are correctly assigned to districts or to implement district changes. The department’s investigation of the 28th House District race was a special project, using a recently acquired and exceptionally limited computer mapping capability to overlay a district map and registration address points to find geographic mismatches. This technology isn’t readily available to many registrars, according to Latham; some use it on an ad hoc basis.

The Post did a similar analysis but looked statewide for these mismatches between the state House of Delegates map and address points. The result – 6,000 misplaced voters – is an estimate because the addresses counted include only those where the most precise map coordinates were readily available. Also, some of the state’s mismatches may since have been corrected.

There were no mismatches at all or fewer than 10 in the majority of the state’s 151 counties and independent cities – 64 percent. Mismatches affecting more than 100 potential voters showed up in 10 percent of localities, and another 10 percent showed mismatches affecting more than 40 registered. The largest concentration was in neighborhoods around Roanoke and the 17th House District. In other areas such as Arlington County, a few address mismatches could involve large residential buildings.

Work by McDonald and Amos shows this is not a problem confined to Virginia. “These errors are happening everywhere,” McDonald said. “If we’re detecting them now in four state legislative districts, my assumption would be that they’re happening for other local district boundaries as well.”

The mistakes may not be common – the thousands of misplaced voters in Virginia and elsewhere pale in comparison to the millions on the voter roll – but as Virginia districts 28 and 94 showed, those misplacements can carry heavy consequences.

Laura Vozzella contributed reporting.