Here is a pretty good summary of what SCOTUS is facing in the Perez case. I don't see anything though about the differing legal standards between Section 2 and Section 5,and what the end game is. It seems more to involve procedural stuff.
This is the exact line from the DC court.
In a ruling critical for Travis County - and Lloyd Doggett - the panel distinguished section 2 cases, holding that states are not obligated to draw crossover districts, with protection of existing crossover districts under section 5:
[F]reedom from an obligation to create a crossover district under Section 2 does not equate to freedom to ignore the reality of an existing crossover district in which minority citizens are able to elect their chosen candidates under Section 5.And the San Antonio court.
Further, under the more stringent
requirements of Section 5, the presence of such districts is relevant for the Section 5
retrogression analysis. See id. at 1249 (citing LULAC v. Perry, 548 U.S. 399, 446 (2006)
(Kennedy, J.) (noting that the presence of districts “where minority voters may not be able to
elect a candidate of choice but can play a substantial, if not decisive, role in the electoral
process” is relevant to the Section 5 analysis). In keeping with the goals of maintaining the
status quo and complying with Section 5 in drawing this map, the Court has preserved district
25 as a crossover district.The concept of crossover districts was dissolved for the purposes of S2. It should now be dissolved for the purposes of S5.
