1. Rope ties together little sibling to a vice president (5)
4. What Congress can or can't do about morality (9)
8. Impose sanctions on reports of colony's prevarications (8)
9. Grave marked with or without the double arches (6)
11. London carriage doesn't ride over the air (11)
13. The waves are endless at a certain large resort (3)
14. All-points bulletin (4)
15. Tattoo's least shallow self-description? (7)
18. Money-grubbing firm keeps control of the purse (7)
20. One's peers determine a sort of rigging (4)
22. First woman arrived the night before (3)
23. A sore thumb might be evidence of this inconsistency (11)
24. Anted up when Bobby got help (4,2)
25. Alternate condition of glass? (4,4)
27. Heraclean status of toe's location? (9)
28. Staffers give poor grades to artificial intelligences (5)

1. Discharge when what's discharged is upon what's not quite unadulterated and corroded (9)
2. Sylvester dozes off at conclaves (6)
3. Familiarly, Hellman's small (3)
4. From Los Angeles to South Africa to old Kiev, the dead man was seen again (7)
5. Page from the south who accepts two types of bonds? (5,6)
6. Superior women know their blood types when confronting dangerous curves (8)
7. What a mistake: sounds like Pooh's friend has the runs (5)
10. Southwest Asian claimed this foodstuff (4)
12. The fluent speechifier, oddly enough, didn't moan in Rhaeto-Romanic (11)
16. One doesn't need three legs to operate these vehicles! (9)
17. Floating substance of the shovel on the Berlin thoroughfare (8)
19. The knight's about, about, about talk (4)
20. Ray and Juan are confused at this time of year (7)
21. Resoundingly achieved the pinnacle of annoyance (6)
22. Banish softness from a certain clothes-size? (5)
26. The German woman mostly became an Italian brother (3)