El Paso is growing faster than the country, but slower than the the state. In 2010, the senate district was extend outward by a few counties, and by 2020 will probably reach Del Rio. Meanwhile the San Antonio-based 23rd was stretched further into El Paso which probably contributed to the election of Pete Gallego of Alpine, defeating San Antonio candidates in both the primary and general election.
Yet El Paso County still has five whole House districts. They were all within 5% of the ideal House district population as of 2010 (but all over 4% on the small side), and the Senate district is only +0.68% (it would have been -1.29% without the four small counties next the east) but it seems odd to me for a single-member upper house district in a state with less than an n:1 lower house member:upper house member ratio to consist of all the territory of n lower house districts plus some more territory.
Does Texas's "county line rule" (the prevailing interpretation of the juxtaposition of requirements in the Texas constitution with the federal "one person, one vote" requirements, last I knew) prevent a county that can have a certain number of whole House districts but they would average less than the ideal (like El Paso County), does it prevent it from having territory outside the county added to that last House district to make the numbers closer?
Also, does the "county line rule" apply to the Senate districts at all? I see at least three partial districts in Dallas County, so I'm thinking no, but that could have been required by some other situation such as VRA requirements.
Yes, the current harmonization of the Texas and US Constitution is that you may not add additional territory outside of El Paso, even though it would make for greater population equality. The current apportionment of five representatives is "good enough" without violating the Texas constitution. "Greater" equality is not preferred if it means violating or even stretching the Texas constitution.
The Texas Constitution provides for 3 types of house districts:
(1) Multi-county single member districts.
(2) Single-County multi-member districts, including single-county single-member districts.
(3) Single member districts apportioned to several counties, based on either the whole county population and the surplus population from one or more type (2) counties.
The Texas Supreme Court has ruled that type (2) counties may be subdivided into single subdistricts for purposes of electing representatives, and the US Constitution (equal protection of racial minorities) mandates it. When Texas first started doing this, they often would designate these districts with a number and a letter suffix (57A, 57B, ... 57K).
Type (3) districts are constitutional for apportionment purpose, but not electoral purposes. If the pre-OMOV interpretation were used, El Paso would elect 4 representatives at large, and then El Paso plus a few small counties would elect a 5th representative. But even though the small counties were providing about 1/4 of the population to apportion the 5th representative, they would have only 4 or 5% of the electorate.
So the Texas Supreme Court has said that you can create a district using an area of the larger county containing the surplus population along with smaller counties. So you could conceivably have a district with El Paso's surplus population beyond 4 districts plus the smaller counties. But the Texas Supreme Court has said that this may only be done if
necessary to comply with equal protection (OMOV).
So in practice there are three types of districts.
(1) Multi-county single member districts.
(2) Single member districts wholly within a county.
(3) Single member districts containing areas with surpluses from one or more large counties, plus all of zero or more small counties.
Type 3 districts don't precisely conform with the Texas Constitution, but are consistent with the underlying principle.
Henderson County is split under the current plan. The triggering cause is that Ellis County has not enough population for its own district, but too much population to be paired with a neighbor - and the belief that it can not be combined with Dallas or Tarrant counties. Since these counties are large enough that you can always create whole districts within 5% deviation, there is a belief that they can not have a partial district.
I think this is wrong. Dallas could have 14 whole districts, plus a small portion attached to Ellis County. This would preserve equal protection, and not completely ignore the Texas Constitution.
This would create a hierarchy for comparing possible plans.
(1) Fewest split small counties. Zero is ideal.
(2) Fewest Type 3 districts with partial surpluses. Consider a county with a surplus of 100,000. It might be possible to take an area with 40,000 and use it as part of a Type 3 district, and another area with 60,000 and use it as part of another Type 3 district. That is the surplus would be split. Zero is ideal, and so could only be used to avoid use of (1).
(3) Fewest Type 3 districts. This gives a preference to using surpluses from multiple counties in a single district (eg Cameron+Hidalgo in current plan; vs the surplus in Cameron in one district; and the surplus in Hidalgo in another district.
The Texas Constitution used to provide that no county could be split to create a senate district.
This went by the wayside after the OMOV decisions. The constitution also provided that senate districts be apportioned on the basis of "qualified electors", which provided a somewhat different basis for the population base of the two houses. Reapportionment guidance was that "qualified electors" could be used if the legislature could find a basis for measuring it - since the census did not.
The 59th legislature (1965) split Harris, Dallas, Bexar, and Tarrant counties, but did it in a way similar to how pseudo-floterial districts are done for the House. Harris had 4 districts, plus a portion of a 5th; Dallas had 3 districts, plus part of a 4th; Bexar had 2 districts, plus part of a 3rd; and Tarrant had one whole district plus part of a 2nd. In addition Cameron was split, with a portion attached to Hidalgo, and the rest going northward to Nueces. There might not have been a convenient way to put Cameron, Hidalgo, and Nueces in two districts, and if you put them into three, it could get ugly.
Confining districts to within the larger counties, maintains as many districts as possible for the other counties - and would give senators from those areas a shot at keeping their seats. So they may have been preserving the sense of the constitution, or the senators may have been preserving their own opportunities.
For the 14 whole county districts, the redistricting law simply lists the counties that comprise the district. The partial county districts are described by metes and bounds, while the mixed districts combine a list of counties, plus a split county (ie "District 9 is composed of Collin, Cooke, Denton, Grayson, Hunt, Kaufman, Rains, and Rockwall Counties and that part of Dallas County not included in Districts 8, 16 and 23.")
This pattern was followed pretty much in 1972. In 1982, some of the splits shifted outward into suburban counties. Traditionally, each house reapportions itself, and with only 31 districts, districts can be somewhat preserved between redistricting. Since all senators are elected after redistricting, there is an added incentive to preserve existing districts. It is more convenient (easier to get a bill passed) to add parts of high growth counties to several districts.
In the 1992-1994-1996-1998 redistricting the splitting of counties went wholesale. District 25 included 8 whole counties, and parts of 9 other counties.
The 2002 redistricting was done by the Republican-dominated Legislative Redistricting Board and cleaned up many of the county splits, but added some if it were convenient to dislodge a Democrat.
The 2012 redistricting was passed on a 29-2 vote, so there are some county splits that reflect wishes of individual senators. There is no reason to split Taylor (Abilene) as the western districts expand to the east. But Taylor was part of a District 24 before, and so you end up with a split, and District 28 wrapping around it.
The senate redistricting provisions in the constitution were edited in 2001, as part of an amendment to "eliminate obsolete, archaic, redundant, and unnecessary provisions and to clarify, update, and harmonize certain provisions of the Texas Constitution." If you read the text of the amendment (HJR 75 (77th RS)), you will see that Texas does not limit constitutional amendments to single subjects.
Notice that there is no longer a population equality standard, or even that redistricting be based on population at all in the Texas Constitution - it is implicitly based entirely on the US Constitution (equal protection).
While they could have stopped with the senate district at the El Paso county line, it doesn't make sense from a community of interest point of view. It is 550 miles from San Antonio to El Paso. The other district is based in San Antonio, but there may have been enough (concentration of) population in El Paso to justify a district office. IIRC, the district lost 60,000 persons from El Paso County, and about 40,000 from the smaller counties. It is unlikely that there would have been an office for the trans-Pecos, and the counties have a much greater affinity with El Paso than distant San Antonio.