The Supreme Court will decide soon whether to take the case of a Texas voter who claims that her vote has been unconstitutionally diluted because her rural district has substantially more voters compared to other, urban districts comprised of many noncitizen, ineligible voters. The claim is that this makes her vote less influential than her counterparts in urban districts. The practical question in this case is whether line-drawers should be using 'total population' or "citizen voting age population' as the measure for drawing equally populated election districts. This Cato Institute article explains the case; Evenwel v. Abbott  in more detail.