Maia, You're always correct! Merriam-Webster's Unabridged Dictionary (in the 'style guide' section) uses "the Enid, Oklahoma plant," without a comma after "Oklahoma." Bryan Garner does not support the comma after a specified year in a full date serving as an adjective: 'The July 16, 2005 meeting was a success.' ... Not 'The July 16, 2005, meeting was a success.' And the same for 'Enid, Oklahoma is my hometown' and 'July 5, 2000 is the date for the renovations. (Again, no comma after 'Oklahoma' or '2000.') Stuttgart, Germany is the location of this momentous event. (No comma after 'Germany' is indeed correct!) Today's style guides favor the commas in these spots. I agree with you that they're wrong. Accolades and kudos to you!
They aren't wrong; it's just that it's a stylistic issue. Most publishers use the CMoS, so in a novels and such, you may find that second comma there.
I suppose a quick way to decide is to leave out the first part of each of these qualifiers...ie, The 2005 meeting was a success, or Oklahoma is my home (state.) You wouldn't put commas there, so it stands to reason you wouldn't use them if they were modifed? I know, I know ...I'm pantsing!
but you're pantsing with wisdom and good common sense [yes, i know that's an oxymoron!], jannert! and that's why any style guide that claims a comma should or can go after the country/state is dead wrong, imo... and thanks for the kudos, dill!... i do have to admit, however, that i am not 'always' right... just 'practically always'! humongo hugs, m