Republican Bob Thomas was sworn in as the representative for the Virginia House of Delegates' 28th District last week following a recount that confirmed him as the winner in the race for the open seat by 73 votes over Democrat Joshua Cole.

Coupled with the decision by Democratic challenger Shelly Simonds to concede the tied race for Virginia's 94th House District to GOP Del. David Yancey following her loss in a lottery-style drawing, the outcome gives Republicans control over the chamber by a 51-49 margin.

But a legal challenge to the 28th District election continues to move forward in the federal courts. And it's shining a spotlight on a somewhat obscure but serious problem related to gerrymandering: split precincts.

A precinct is usually the smallest administrative unit in an election district, with a specific place where all eligible residents go to vote. But a split precinct is divided by one or more election district lines, meaning some precinct residents vote in one race and some in another. Split precincts require multiple versions of the ballot, creating potential for confusion among poll workers.

That's exactly what happened in Virginia this past Election Day. Poll workers in the Fredericksburg area gave the wrong ballot to at least 147 people, sparking an ongoing federal lawsuit filed by voters seeking a new election for the House seat.

The problem of split precincts has grown along with gerrymandering, as politicians in charge of drawing election district maps have prioritized concerns such as partisan advantage and racial division over ease of election administration.

The 2011 redistricting process in Virginia led to what the Williams & Mary Law School blog characterized as an "explosion of split precincts" driven by a sharply divided legislature, the desire to protect incumbents, and improved technology allowing house-by-house precision in drawing election district maps:

According to research done by the Virginia State Board of Elections (SBE) staff, the 1991 Virginia redistricting plan created 102 split precincts from a total of 2133 precincts and the 2001 plan created 75 split precincts from a total of 2239 precincts, healing some of the 1991 splits. In 2011, there are 2376 total precincts in Virginia. Of those, the most recent round of redistricting carved up 224 precincts into more than one piece; three times the number of split precincts created in the last round of redistricting.

The initial proposal considered during Virginia's most recent redistricting process would have split 500 precincts. Lawmakers worked to lower that number; after then-Gov. Bob McDonnell (R) vetoed the first version of the legislature's maps, they whittled it down further.

Besides increasing the chances for poll worker error, split precincts cost taxpayers more. They require not only multiple ballots but also pre-election materials to educate voters about district line shifts as well as polling place signage to ensure voters get the right ballot. The additional costs of a single split precinct have been estimated at up to $25,000.

Dividing North Carolina

Split precincts are also a problem in other gerrymandered Southern states like Alabama and South Carolina. But perhaps no state has gone so far to divide local communities for partisan political ends as North Carolina.

The election maps that the state's Republican-controlled legislature drew in 2011 created 563 split precincts that are home to more than 2 million voting-age adults — a quarter of North Carolina's voting-age population. That's more than twice as many splits as under any of that state's previous redistricting plans. In one of the more extreme examples, one six-block area of Durham County had so many district lines running through it that it could potentially require 18 ballot versions.

The split precincts have caused problems in North Carolina's elections. During the 2012 election, for example, hundreds of voters across the state received the wrong ballots because of confusion over what district they lived in, with communities of color disproportionately affected. Research by Democracy North Carolina found that black voters are 50 percent more likely than white voters to live in a split precinct.

The legal challenges to the North Carolina maps pointed out that split precincts make it harder for voters to cast ballots and essentially create two classes of voters. The challengers also argued that split precincts violate the state constitution, which calls for redistricting to keep counties — not just precincts — whole to the greatest extent possible.

In addition, voting rights advocates point out that split precincts jeopardize the secrecy of the ballot. As Kellie Hopkins, elections director in North Carolina's Beaufort County, noted in a 2012 affidavit, "By having such a small number of voters with a ballot style, I am afraid that reporting by [precinct], which is required by law, could possibly allow others to know how someone marked their ballot."

The federal courts have ruled that the North Carolina legislative districts drawn in 2011 included unconstitutional racial gerrymanders and ordered lawmakers to draw new ones. Among the criteria lawmakers adopted to guide their redrawn maps was the requirement to "make reasonable efforts" to split fewer precincts.

But, dissatisfied with lawmakers' efforts to undo racial gerrymanders, the courts assigned a special master to redraw the maps — Stanford University professor and redistricting expert Nathan Persily. His plan does not add any more split precincts and in, fact, unifies some precincts that were split in the original 2011 plan or 2017 legislative revision.

A panel of federal judges is currently considering which version of the maps to use. A decision is expected soon as filing for legislative races is set to begin on Feb. 12.