Theme:   If you’ve been to my site before, you may recall my suggestion to look through all the clues quickly to see if there’s on that ties them together to form the “theme.”  There’s one today (54-across), though it doesn’t make much sense to me at first.  What a convoluted phrase!  Once you get a couple long across answers, this’ll become clearer.   If you have no idea what the 1977 Boz Scaggs’ hit was, it’ll be a big help to get 27- and 45-across first.

Frequent, as a club:  3 words.

One side in the Falklands War:  They couldn’t even agree on what to call it.  The side in question calls it the Malvinas War.

What a horseshoer shoes:  You’d think it’d have an “S” at the end.  It doesn’t.

Film Terrier played by Skippy:  Is it wrong for a male dog to play a female dog role?  Is there another 4-letter movie dog?  Oh, yeh, TOTO.  Well, this isn’t him.  Or her, for all I know.

“Picnic” playwright:  What a door swings on to Brit (with a Cockney accent)?  Remember this one, it’s nearly as common as the aforementioned dog.

Common cotton swab:  a violator of one of the most regular rules in English.

Bird with red-eyed and yellow-throated varieties:  As if “red-eyed and yellow-throated varieties” is gonna help much.   It’s a bird, that’s all.  Close to something that should be on YouTube.  Anyway, once you get it, remember it:  Seems to be popular in crosswords these days.

Hankering:  one step stronger than an ITCH.

Volga River native:  I would have though these folks were gone centuries ago.  I checked, though, and there are still millions of ’em.

1974 John Wayne crime drama:  Apparently he arrested all the vowels.