Across:
   4. see 14 down
   8. Some star comedian turned politician (8)
   9,28. Person to embrace, strangely starry 11 16 across (5 1. 6)
  10,18. He nearly lead before race taking turn - everyone dumped popular vice of 12 23! (5 1. 7)
  11. Female, single... our number one state? (8)
  12,23. Legendary leader blunt and carefree tackling independent and Republican, with left in check (8 1. 9)
  13. Foreign article, advertisements and editorials (5)
  16. Politician's terrible treason (7)
  18. see 10
  21. Trap set before leader of youth group (5)
  23. see 12
  26. Schemed as criminal deposing leader, dispatched like Julius Caesar (8)
  27. Observing very very little... not hard! (6)
  28. see 9
  29. Such matters interested 10 18... getting bits of real advances into wheat perhaps? (8)
  30. Some of the heartiest part of cereal crop (3)
Down:
   1. Practise butt wiggling here first (8)
   2. Sources of medicine offering this reputed ibuprofen name? (6)
   3. Sweeper carries amazing load, perhaps 3.66m (9)
   4. Ability to keep going enlivens when bouncing back after loss of energy (7)
   5. Somehow his kitchen should include this? (5)
   6. Wild boar not imagined to be tree dwelling (8)
   7. Breaking apathy, bridge which 10 18 developed to improve crop exports? (6)
  14,4ac. Spot noticed it has its ups and downs (3-3)
  15. Mecca's sand raised to show the true prophet that everyone doubted (9)
  16. Exhaust fool (3)
  17. Reverse words my "not" naturally conveys? (8)
  19. One way of approaching world uprising... partly plain ol' occupation! (8)
  20. Century before, world foolishly embraced one conflict that 10 18 wanted to avoid (4 3)
  22. Ready to travel on with a poet embracing love (6)
  24. Strove to get around those theoretically important to a 8? (6)
  25. Leaders of old variety impede new efforts like sheep (5)
Solution:
=R=M=B=SAW=A=H=|
DEMOCRAT=HARRYS|
=H=T=O=A=I=B=B=|
HENRYA=MISSOURI|
=A=I=D=I=K=R=I=|
FRANKLIND=LEADS|
=S===O=A=C=A==E|
SENATOR=WALLACE|
A==N=M=C=S===O=|
PARTY=ROOSEVELT|
=B=O=O=L=A=O=O=|
CONNIVED=NOTING|
=A=Y=I=W=D=E=I=|
TRUMAN=AGRARIAN|
=D=S=EAR=A=S=L=|
Name: Puzzle 846 - Popular Vice
Author: by BenDR