sentences:  Najder returned to his homeland, serving as a key adviser to Lech Wałęsa during his presidency (1990–95) and a senior adviser to Jan Olszewski during his term as prime minister (1991–92).In 1992 he became central to a controversy in Poland when Jerzy Urban published in the left-wing Polish weekly tabloid magazine "NIE" a document purportedly written by Najder in 1958, stating that he would cooperate with the Communist secret police.Urban was accused and convicted of violating Poland's state secrets act.