20. Cuban missile crisis strategy: NAVAL EMBARGO. A VALE is a long depression in the land, usually between two hills and containing a river.
31. Web app for the latest: GOOGLE NEWS. A GLEN is a valley that is long and bounded by gently sloped concave sides.
41. Pre-wedding show: BRIDAL EXPO. DALE is a synonym of the word valley.
Melissa here. Grokking this theme would have been more difficult without the circles. See the valley hidden in each theme answer? I can imagine the light going on in George Jasper's head when seeing the words 'Hidden Valley.'
Across:
1. Bare-bones: BASIC.
6. Out of concern that: LEST.
10. Distance runner's concern: PACE. Cramp or spasm was my first thought - too many letters.
14. Early Greek public space: AGORA. The agora (ἀγορά) was a central public space in ancient Greek city-states. It is the best representation of a city-state's response to accommodate the social and political order of the polis. The literal meaning of the word "agora" is "gathering place" or "assembly."
15. Excessively: Pref.: OVER.
16. Aerosol target: ODOR. Not hair.
17. Mall map clarification: YOU ARE HERE. Carl Sagan's Pale Blue Dot.
19. Half a patio pair: TONG. First thought was chairs.
22. Uncertainties: IFS.
25. Even the queen, in chess: MAN. Not necessarily. Another interesting fact for those who watched The Queen's Gambit, in this NYT article. If you can't get past the NYT paywall, here's a different article about the same thing, with a link to the 25-page complaint.
26. Beat in a hot dog contest: OUTEAT. I can't watch those eating contests. Because ew.
27. Like nobility: TITLED.
29. Slow movement: LARGO.
33. What 15 U.S. presidents formerly were, briefly: VPS. I would have guessed more than 15.
36. Son of Chingachgook, in a Cooper novel: UNCAS.
37. Be in the red: OWE.
38. Hustle: CHEAT. Or this hustle.
40. Shaggy pack animal: YAK.
43. Frequents dive bars, say: SLUMS.
45. Pretentious type: POSEUR. Another term for poser - someone who pretends to be something he is not.
46. Key participant: PLAYER.
49. NBA tiebreakers: OTS. Overtimes.
50. Water holder: DAM.
55. Opposed to, in dialect: AGIN. Surprisingly, AGIN is a valid Scrabble word.
56. Start of a proverb for which Ben Franklin is credited: EARLY TO BED. "... early to rise, makes a man healthy, wealthy, and wise."
60. It's about a foot: SHOE.
61. "Star Trek: T.N.G." counselor: TROI.
63. Online craft shop: ETSY.
64. Newcastle's river: TYNE.
65. Summer Triangle star: DENEB. The Summer Triangle is an amalgamation of stars from three separate constellations. Three stars make up the triangle: Deneb, Vega and Altair.
Down:
1. __ window: BAY.
2. Before now: AGO.
3. Thing of little worth: SOU. A thing of the smallest value. Not sure I've ever heard this word.
4. Turkey neighbor: IRAN.
5. Whitman's Sampler choices: CARAMELS.
6. "Freaky Friday" actress Lindsay: LOHAN.
7. First name in daredevilry: EVEL. 8 of Evel Knievel’s Most Memorable Stunts.
8. Saharan: SERE.
9. Shakes: TREMORS.
10. One may be sweet: POTATO. Obscure clue, perps to the rescue.
11. Love to death: ADORE.
12. __ line: CONGA.
13. Cereal killer: ERGOT. Another unknown for me. A fungal disease of rye and other cereals in which black elongated fruiting bodies grow in the ears of the cereal.
18. Artfully escape: EVADE.
21. Listening device: BUG. Has anyone seen the documentary MLK/FBI?
22. Company's tech guru: IT GUY.
23. "Shrek" princess: FIONA.
24. Keep in the supply room: STOCK.
28. NYC airport on Flushing Bay: LGA. LaGuardia Airport is a civil airport in East Elmhurst, Queens, New York City.
29. Civil rights legend John: LEWIS. February 21, 1940 - July 17, 2020.
30. Blown away: AWED.
32. What do you expect?: NORM. Nice clue.
33. Put out: VEXED.
34. __ New Guinea: PAPUA.
35. Perfect thing that's not beneficial: STORM. The Perfect Storm is a great book and movie.
38. Like idiomatic skeletons: CLOSETED.
39. Tom, Dick and Harry: HES. Not men.
41. TV host/comedian with 23 Emmy nominations: BURNETT. Carol.
42. In a suitable manner: APTLY.
43. New South Wales capital: SYDNEY.
44. Jeans brand: LEE.
46. Part of a process: PHASE.
47. __-year: LIGHT. The distance light travels in one year. Or this guy ...
48. "So long, amigo": ADIOS.
49. Skateboard move: OLLIE. The trick that revolutionized skateboarding.
52. Fluctuate: VARY.
53. "East of Eden" twin: ARON.
54. Bygone days: YORE.
57. Stop legally: BAN.
58. Austin-to-Houston dir.: ESE.