From SCOTUS blog:

Yesterday the Acting Solicitor General filed an invitation brief in Iron Thunderhorse v. Pierce (09-1353), recommending that the Court deny certiorari or, in the alternative, grant certiorari and summarily reverse and remand the Fifth Circuit’s ruling for application of the correct legal standard.  At issue in the case is whether the court of appeals misinterpreted the Religious Land Use and Institutionalized Persons Act to require only a minimal showing that a prison grooming rule which concededly imposes a substantial burden on religious exercise is the “least restrictive means of furthering [a] compelling governmental interest.”  The Acting Solicitor General’s brief is available here.

An excerpt, where the OSG argues that the Fifth Circuit made a gross error:

But petitioner in this case raised arguments and evidence not addressed in Diaz or Longoria: that other prison systems (including the federal Bureau of Prisons)permit long hair, and that TDCJ enforces its grooming policy in an inconsistent manner. Id. at 10a n.3. Thecourts below, however, never required respondents to explain why the alternative, less restrictive practices utilized in other prison systems would not work in the Polunsky unit. Nor did they require prison administrators to explain why the previous inconsistent application of the grooming policy to petitioner and to others (including Texas’’s female inmate population) did not indicatethat a less restrictive alternative was appropriate. See ibid. Although respondent acknowledges (Br. in Opp. 14-15 (citing Odneal, supra)) that the Fifth Circuit requires prison officials to justify application of a challenged policy under the facts of a particular case, respondent notably does not even attempt to justify the court of appeals’’ refusal to hold officials to that standard in this case.

The petition stage materials are here.