When Sam walks into the conference room late in the episode and says "I want to state right here, right now, in terms so plain and clear as to command their assent . . . " he is paraphrasing Thomas Jefferson's explanation for the purpose of the Declaration of Independence. Jefferson stated its purpose was ". . . to place before mankind the common sense of the subject, in terms so plain and firm as to command their assent . . ."
The trivia items below may give away important plot points.
The screening of '18th and Potomac' was first shown in Australia on the evening of September 11 2001. A newsflash about the two aircraft hitting the World Trade Centre was broadcast in the last commercial break. The remaining ten minutes of the West Wing was then screened, which coincidentally involved the unexpected death of a major West Wing character.
As Deaf pollster Joey Lucas starts to report polling results to the president and senior staff members during the secret meeting in the basement, President Bartlett interrupts her to ask if anyone in the room knows Kenny's last name. However, in S1-E14 " Take This Sabbath Day", Josh Lymon introduced Joey Lucas and her interpreter Kenny Thurman to the president as he roamed the halls of the White House contemplating whether or not to pardon a deathrow inmate about to be executed.