Senate Rule 19 includes this prohibition: "No Senator in debate shall, directly or indirectly, by any form of words impute to another Senator or to other Senators any conduct or motive unworthy or unbecoming a Senator." ...
She criticized Jeff Sessions, a Republican senator from Alabama and the nominee to lead the Justice Department. ...
According to Senate Republicans, Warren impugned the "conduct or motive" of Sessions, who is expected to be confirmed as attorney general Wednesday night.
Warren's supporters saw a stifling of dissent, and asked how the mere reading a letter could violate the rule.