Cryptic crossword No 3,963

Across

1. Silence stifles US police's case (6)
2. Entertainers drinking whiskey, becoming wife-swappers? (8)
3. Frequently producing endless anti-abortion invective, caustic primarily (8)
4. Some may do bondage on the counter...not a lot (6)
5. Common in rubbish bin, a peel (8)
6. Aching regularly, backside slashed, getting herbal products (6)
7. Study other side in match, but proceed stealthily (6)
8. This might result from electronic situation with buzz surrounding it (9)
9. Pork pies origin of fatal digestive complaint (4)
10. Essentially evaluate take-away containing egg as "brilliant" (8)
11. Ruler has politician ousted by government, making exit (6)
12. Ridesharing service withdrawn, facing very strong setback (6)
13. Come with coin, unexpectedly giving opportunity for profit (8)
14. Perhaps Sam joins new church to open up (8)
15. Using bits from red algae, gelatinous additive brought about (4)
16. Silly cape tailored for important occasion? (9)

Down

1. Delivery of tree, pine, for many yards (7)
2. Motivated, curious birders ultimately see tit (9)
3. Announcing that woman's losing hair, covering head (9)
4. On Harry's debut, United force penalties, followed by singular indignation (9)
5. Seafood pitcher? (7)
6. Plant timeless image for general viewing somewhere in California, bolstering publicity (7)
7. Unfavourable opinion about English guaranteed (7)
8. So what if setter's beset by bad leg at work? (3,4)
9. They're far from spineless, taking part in heroic activity (5)
10. Sly character can be rough (5)
11. Unwrapped item near our cycling path (5)
12. Parody of vacuous soap that's got to hurt (5)
13. Trendy pop group displaying curvy parts of anatomy (7)
14. Choosing between two men? Way to mark time! (9)