Is it grammatically correct to capitalize all of those words?

[Quetzalcoatl]

One thing in regards to English grammar that has somewhat perplexed me is the amount of capitalizations that Donald Trump does when he tweets. I know that you guys capitalize a lot of words that we don't (for example, the names of months, the names of weekdays, religions, and nationalities), but even then, it seems like those tweets go over the top.

Consider the following very recent tweet from Trump:

https://twitter.com/realDonaldTrump/status/1162414717505277952

Should the words "great", "state", "agenda", "crime, "strong", "borders", "full", "complete", and "endorsement" in this tweet be capitalized? My understanding of English grammar is that they should not. I understand that "Second Amendment" should be capitalized, as those amendments typically are, as they are names for specific amendments.

[The Latinist]

If one thinks about “State of ____” as a proper noun -- the full name of the state -- one might capitalize State (e.g., “The capital of the State of Vermont is Montpelier”).  But Virginia’s full name is not the “State of Virginia” but the “Commonwealth of Virginia,” so either way it’s wrong.

[Soldier of FORTRAN]

The conservative love of randomly emphasizing things with caps, quotes, etc. is a long-standing mystery and the subject of much speculation.

But the non-standard use I'm familiar with is giving something a slightly stilted feel for emphasis.  Capitalization's evocative of proper nouns, slogans and titles.  You can steal that to breaks the flow and confer emphasis. 

e.g. [This is something you see a lot of from conservatives.]  vs [This is A Thing for conservatives.]

[jt512]

The conservative love of randomly emphasizing things with caps, quotes, etc. is a long-standing mystery and the subject of much speculation.

I think it's called illiteracy.

[daniel1948]

"Is it correct to capitalize all of those words?"

No. It's not.

But honestly, if he wasn't fucking the entire nation in the ass every day, I wouldn't care about his grammar.

[Rai]

It looks weird, but I can kinda see a logic behind it.

Twitter has no built-in formatting options, so underlining, italicising and bolding are not available as options to put a visual emphasis on words, so all is left is capitalising and all caps, the latter of which has a very specific use.

There is no correct or incorrect way of using language as long as it remains comprehensible to the audience. Prescriptivism is the worst.

[bachfiend]

English used to capitalize all nouns, the same as German.  Danish used to capitalize all nouns too, but I think that sometime after 1945, it was agreed that nouns generally wouldn’t be capitalized.  At the last ‘reform’ of the German language, it was proposed that it would stop capitalizing nouns too, but it didn’t happen.  The major reform was that ‚daß‘ would now be spelt ‚dass.‘

Personally, I don’t mind some nouns being capitalized, when they shouldn’t.  I prefer ‘Winter’ to ‘winter.’  It goes along with capitalizing the months of the year and the days of the week.  I know I’m wrong, but I can’t help it.  If I remember, I use the non-capitalized form.

[arthwollipot]

Correct grammar is to capitalise only proper nouns, and the first letter of a sentence.

[bachfiend]

Correct grammar is to capitalise only proper nouns, and the first letter of a sentence.

Ok, i’ll go along with that.  Foolishly, i’d believed that ‘i’ should be capitalized, but it seems i’m wrong, since it’s not a proper noun.

https://en.m.wikipedia.org/wiki/Proper_noun

[The Latinist]

Word in titles are also capitalized, except for articles, coordinating conjunctions, and prepositions.

[arthwollipot]

Word in titles are also capitalized, except for articles, coordinating conjunctions, and prepositions.

True. Good catch.

[bachfiend]

Word in titles are also capitalized, except for articles, coordinating conjunctions, and prepositions.

True. Good catch.

There was the poet e e cummings, who capitalized virtually nothing:

https://en.m.wikipedia.org/wiki/E._E._Cummings

I was disappointed that his headstone put everything in capital letters.

Perhaps you ought to change your signature?  ‘He’ and Him’ aren’t proper names.  Nor are they at the start of a sentence.

[Calinthalus]

iPreferCamelCaseForCapitalization

[Rai]

Correct grammar is to capitalise only proper nouns, and the first letter of a sentence.

If I wanted to be pedantic, I'd say that capitalisation, along with spelling, word spacing, punctuation, etc. are orthography and not grammar.

[DevoutCatalyst]

iPreferCamelCaseForCapitalization

As well you should if that's your thing.

I have a smallcaps font installed as the default in my browsers set to overwrite the font selections of all Internet page creators. Other than a minor height difference between cases in this particular font, for me it's all caps all the time at every site. For years now.

I don't deny what the others said is true and also note that no one here uses diæresis -- if you wrote for The New Yorker you'd have to coöperate with them. There are stylistic choices people make and only a jury of your peers to let you hear about it if you go too far.

I'm amused when a few skeptics I know get all butthurt over the random person that writes something in all caps. Interesting behavioral choice, butthurt. But then I'm a capitalist, what do I know.