The act of gerrymandering—redrawing voting districts to benefit a party—is often divided into two tactics: cracking and packing.
Gerrymandering happens by either cracking apart a district with an opposition majority into separate districts without that majority, or by packing opposition party voters into one district, limiting their majority to a single district.
But large non-voting populations, like non-citizen immigrants and felons, may also define another gerrymandering tactic that could be considered filling—packing a district with non-voting representatives that might otherwise go to opposition party votes.
While non-citizens can’t vote, they do count towards Census population counts when determining district sizes.
The effect of large non-voting populations on redistricting in this way was very present in the most recent round of congressional redistricting following the 2010 census.
During that redistricting, a number of newly defined districts added large, non-voting populations. The resulting boundaries led to a flip in the default vote in the following elections.
Prior to 2010, Columbus, Ohio and its surrounding area was represented by three districts that shared parts of the city: the 12th, 15th, and 7th.
The 2010 census created a new district—Ohio’s 3rd —centered on Columbus, carved out of the 12th, 15th, and 7th. Previously the 3rd district had been on Ohio’s far western edge at the border of Indiana.
Besides the new district having boundaries surrounding more Democratic voters, it also included a sizable number of non-citizens. According to the 2017 census, the new district had an outsized non-citizen population—6.45 percent—the largest in the state.
The 3rd district had the largest percentage point increase in non-citizens in the nation between 2008 and 2017.
The almost 50,000 non-citizens in the 3rd district effectively filled up what might otherwise be voters of Democratic or Republican stripes.
The newly created district became a Democratic stronghold, with the last three Congressional elections readily won by Joyce Beatty (Dem.-OH). Previously, the three separate districts that comprised Columbus were staunchly Republican.
The 2010 census also rearranged Tennessee’s 4th district, which originally reached from the bottom middle of the state to the top border with Kentucky including the city of La Follette.
The new district now includes a curved loop that curves around the north side of Chattanooga, which sits on the southern border of the state.
The changes almost tripled the district’s non-citizen population. It also switched the district from a regular Democratic seat held by Lincoln Davis (Dem.-TN) since 2002 to a steady Republican win for Scott DesJarlais (Rep.-TN) from 2010 on.
The new non-citizen voting population (~24,000) was slightly smaller than the number of votes DesJarlais won by in 2012 (~26,000), although it’s undetermined how those voters would have sided if the district was apportioned differently and they were eligible to vote.
The sixth district of Maryland encompassed the complete Western panhandle of the state going back before 2000 that extended East across the Northern border of the state above Baltimore.
But the 2010 Census removed that Eastern section above Baltimore and replaced it with a chunk of Montgomery County.
The ensuing district went from 2.5 percent non-citizens to 9.5 percent, or 54,000 additional non-citizens.
The district that was regularly won by Republican Roscoe Bartlett (Rep.-MD) immediately flipped to Democratic candidate John Delaney (Dem.-MD).