When David Patrick Stearns first heard Jacqueline du Pre’s 1970 recording of the Dvořák Cello Concerto, he thought she “sounded like a freedom fighter.” Turns out he was right: she had played the work in a protest concert shortly after the 1968 Soviet invasion of Czechoslovakia. Stearns looks at other examples, from Wilhelm Furtwängler conducting Tchaikovsky just after Kristallnacht to Ormandy and the Philadelphia Orchestra playing Shostakovich in the Soviet Union to Bernstein performing Mahler’s “Resurrection” Symphony after JFK’s assassination to, perhaps, James Levine leading Verdi’s Requiem last week.