Across:
   1. Truman called him "a weak, trivial thumb-twaddler", confusing central part of film lore (8)
   5. Roosevelt swept him away with vacuum cleaner (6)
  10. Vexed when seniority was prevailing (7)
  11. Stepped down, about ready for a rest (7)
  12. Try for US landing? (9)
  13. Study is about famous figures (5)
  14. Repudiate a brother with exit (8)
  16. Dash of beaver's tail in meat dish (6)
  19. American culture: patchwork toy rug (6)
  21. "Gas" (fuel) made Henry God (8)
  24. It's put on head of anti-Arafat group (5)
  25. Reckless drive where French involved (9)
  27. Experience of world body - the German and Japanese game (7)
  28. No limits for land of state (7)
  29. Stab unpopular leader (6)
  30. He popped into office briefly, or ran his letters (8)
Down:
   1. What every president except Buchanan had is flat dry cocktail (5 4)
   2. Both hands used to hold guano mixture, hence fatigue (7)
   3. Mighty useful layer covering healthy roots (5)
   4. Cast rode about as soldiers (8)
   6. He might carry bowlers or tote fruit cocktail (9)
   7. Return of a little sob revealed having much to say (7)
   8. Dries out for rodeo performances (5)
   9. Philippic pursues Good Ulysses (5)
  15. Nigeria tricksters snared elderly (9)
  17. East Caribbean capital, after West invaded West Caribbean capital (9)
  18. Holy map redrawn around millennial symbol for cancer (8)
  20. Hotshot in bigwig ran deep (7)
  22. Remains as basis (7)
  23. Bad president? Nothing on this guy! (5)
  24. The head bum, Donald (5)
  26. Falling back, rely on the first "accidental president" (5)