“A measure expanding lower federal courts by 250 judges can be enacted through the budget reconciliation process, which is not subject to the filibuster, and which needs only a simple 51-vote majority to pass the Senate,” Mr. Moyn and Mr. Belkin said in a joint statement. The pressure comes as progressives have also pushed for expanding the high court to counter the 6-3 conservative majority. But liberal Supreme Court Justice Stephen G. Breyer poured cold water on that call Tuesday, saying it would make the court appear political. The activists said lower courts face a backlog of cases, pointing to Arkansas Eastern District Judge Brian S. Miller, a Republican appointee, who said the “increasing caseloads lead to significant delays in the consideration of cases, especially civil cases which may take years to get to trial.”