Feb. 1 marks the first day of Black History Month, and suddenly the study of the Black experience may feel like an act of defiance. Feb. 1 is the beginning of Black History Month, which for decades has recognized the contributions of Black people to American civic life and culture with festive luncheons, serious lectures, profitable merchandise lines and staid White House receptions. But a month that was officially recognized nearly five decades ago by a Republican president, Gerald R. Ford, is dawning this year with new significance amid President Trump’s furious assault on diversity programs inside and outside the…