Across:
   1. Set if I do sly adjustment (8)
   5. see 21 down
  10,1dn. Brief 23 employee has cut - acrimony can brew (7 10)
  11. Republic's shaken with 150 dismissed and chief of staff dumped by 23 (7)
  12. Broadway hit more cautious, with wings clipped (5)
  13. Death scores in chaos (8)
  15. One leaves blues train confused and not so steady (9)
  17. Head off hunter as symbol of US power (5)
  18. Left out attractive FBI head who fell foul of 23 (5)
  20. Farmer and young Rex hired and fired by 23 (9)
  22. Cast cite trouble with "Joy" (8)
  25. No repetition in smashing of pewter mug (5)
  27. Cleverly glued each in and formed a combined entity (7)
  28. Strangely chirpy about the end of our worst sort of win (7)
  29. Agent cut but coming back - they are often removed (6)
  30. A US president claimed to be one from timberline residence (8)
Down:
   1. see 10 across
   2. Being sent back in person, Italians and Mexicans perhaps (7)
   3. Finally build Rome in a day with right beast (9)
   4. see 19
   6. Friend of 2 am I? Get out of here! (5)
   7. In Australia, bank on Crosby being arresting (7)
   8. One's tits contained here? (4)
   9. As ghost dancing, rest clap (8)
  14. Lunatic spares nice fellow who spoke for 23 (4 6)
  16. Freedom to swap first two in height (8)
  17. Cell are to reform, involving a ballot  (9)
  19,4. Destroy life - lynch man who was cast out by 23 (7 5)
  21,5ac. No naps?! Then Ben's out... he's not working for 23 any more! (7 6)
  23. Somewhat rum politician? (5)
  24. Police note some greenery (5)
  26. Two thirds steal and turn (4)