### Clue: About to receive papers on Republican's addition to bill (5)
### Answer: RIDER 
 ### Explanation: Definition: addition to bill
  [RE(Edit.note re comment#2: ~~short~~ Latin for regarding,about) **containing**(to receive) ID(abbrev. for identification,papers that prove you are who you are, perhaps?)] **placed above**(on, in a down clue) R(abbrev. for a member of the Republican Party).