Assange has been in self-imposed exile at an embassy in London for more than four years, to avoid extradition to Sweden on sexual assault charges. He could face espionage charges in the U.S.
The charge, according to reports, is obstruction of justice.
His attackers appeared to be neo-Nazi sympathizers.
Agitated but compliant, the senator answered Sen. Patrick Leahy's question about Trump's 2005 "grab them by the pussy" claim, and whether such actions would be unlawful without a woman's consent.
The unrepentant white supremacist, who fatally shot nine black church members during a Bible study session, is the first person ordered to be executed for a federal hate crime.
Community members in South Dakota are mourning the loss of the two-spirit transgender woman.