I think there are several (language) problems with this text, but to answer your question, I don't think the semicolon works here. Yes, you have two independent but related ideas: The US didn't intervene, and this was because ..., but each idea is quite long in itself, and you end up with a very long sentence.

Furthermore, you already have two contrasting ideas in the first section - "Despite many years of ..." and "the US didn't intervene". So your first idea is not so much about the US's non-intervention, but about the contrast. Your next part, about their reasoning, may be related to the non-intervention,but not really to this contrast. Personally, I feel that "officially ended" cries out for a natural break, and a full stop (period) would be much more appropriate here.

Now for the colon; its position is fine, but I'm concerned about what comes after it. I feel if you use "include" here we expect a list of things, i.e. noun phrases, but you have standard sentences. Secondly "reasoning" is uncountable, so no "s" at the end. I would suggest something like: "Their reasoning behind not interfering was based on several factors: the US was in a time of ... etc".

@porsche - Sorry to put a spanner in the works, but "She was sat at the bar", as used idiomatically in British English, means precisely "was sitting", and has nothing to do with being placed there by anyone. Similarly in "I was stood at the street corner watching the traffic go by." Nobody "stood" me there. To that extent, Brus is correct.

Although I think a theoretical grammatical explanation can be put forward for it, which I tried to do in an earlier comment, what it really boils down to is this is an idiomatic expression which is becoming increasingly popular among speakers of Standard British English. Many authorities, Fowler for one, believe(d) that established idiomatic use supersedes theoretical grammar. I grant you that "was sat" is still borderline, but it is very evident listening to BBC Radio 4 (the most "Standard" of British radio stations) that its use is becoming increasingly common among non-dialect speakers.My bet is that in twenty years or so, few people will remember what all the fuss was about.

@MBS - Forget my last comment. I presume "So I am writing a historical novel" means something like "Supposing I were writing a historical novel" - it doesn't mean you actually are. Anyway, it was quite fun to research.

Forget Word, Firefox doesn't like either of them either, but the far superior spell check in Google docs, which is contextually based, accepts both. Judging by Google Books, you could go either way, but it seems to be nearly 2:1 in favour of Montgomerys (15,800 to 8,200). There is, for example, "A Genealogical History of the Montgomerys and Their Descendants" by a certain David B.Montgomery.

And while there's an 1859 book "Memorials of the Montgomeries, earls of Eglinton" the Wikipedia entry on Clan Montgomery shows the coat of arms of the Montgomerys, Earls of Eglinton.

There is a further complication in that, according to the Clan Montgomery website, some people have the surname Montgomerie, which would boost the IE figures. Incidentally, that website seems to use exclusively "Montgomerys" when talking of various Montgomery families.

http://www.clanmontgomery.org/links.html

This Ngram graph suggests that the Y version overtook the IE version around 1910, and that the Y version is much more common nowadays.

http://books.google.com/ngrams/graph?content=the+Montgomeries%2Cthe+Montgomerys&year_start=1800&year_end=2000&corpus=15&smoothing=3&share=

Small point. If you're writing a historical novel, shouldn't you have been doing this sort of research already?

@qurat - "Ali hasn't had breakfast this morning" - is perfectly correct, as long as we are still in the morning, in which case we are talking about the current time period. In theory, at least, Ali could still have breakfast this morning, so present perfect is the right tense to use (in British English, in any case).

If it's the afternoon or later however, past simple would be more appropriate - "Ali didn't have breakfast this morning".

If by any chance you're translating from Spanish, the rules for using pretérito perfecto with present time periods, and pretérito indefinido with and past time periods, are exactly the same as in English.

Where it gets a bit more complicated is with expressions like today, which can be divided up into parts:

Salesman to his colleague at 4pm - I've opened four new accounts today.
Same man to his wife at 8pm - I opened four new accounts today.

You might think that "today" was the current time period in both cases, so both should have present perfect. But in the second case he is really thinking of his working day, which is now finished, and so a past time period.

@Ray Riems - I think you're the one who's having difficulty reading English, as you somewhat misquote John, who has been one of the few people on this post to talk any sense, along with JJMBallantyne and Douglas.Bryant, who unfortunately seem to have given up on this forum.

What John actually said was "Who makes the rules of English grammar, if not the users of English?". He neither said "makes up" nor "an English speaker". And nor did anyone else, as far as I can see. What they talked about was "common usage", something very different from your interpretation.

And of course he is (they are) perfectly correct; the rules of any language come from what generations of speakers of that language (or specific dialect, for example Standard English) have decided is acceptable: that's where grammar comes from. It's only later that it gets codified in grammar books. The earliest English grammar books recognised this, as do most modern grammars. Unfortunately, in between we had the prescriptivists, who tried to carve certain rules into stone, and even more unfortunately, some people still take the same attitude.

Before advising people to "get a grip" and accusing others of making "idiotic submissions", perhaps you should try engaging your own brain, or at least learn how to read.

@Brus - I'm not sure how terms can "pretend to be standard English" or not, but that's by the by. Standard English is the form that is acceptable to a majority of native speakers. Sometimes that form includes idiomatic expressions that break "the rules", or at least somebody's rules, for example some pedants call "Who said that? - It was me" and "Who were you speaking to, just then?" incorrect, yet they are perfectly standard.

I would suggest that is exactly what is happening in Britain with "he was sat". It is now often used by people who speak otherwise totally standard British English, and for many (probably most) of us poses absolutely no problem, however much some people cry "incorrect". We've heard it all before: for "ten items or less", for "that" instead of "which"etc. If we are sensible we simply ignore it; the more inquisitive of us try to find an explanation, as I tried to do in my last comment.

Grammar doesn't come from books or immutable laws; it has been formed by generations of native speakers arriving at a consensus as to what is acceptable. I don't hear much outcry in Britain at the increasing use of this (to me rather attractive) idiom. And so what if it is dialect? (After all Standard English is also only a dialect, linguistically speaking). Some of us would welcome a little more dialect in realms where Standard English has traditionally held sway: on the BBC, for example.

@Melvis D. Dixon - People in glass houses. Perhaps somebody who talks about Obama being elected governor of Chicago (or perhaps you mean Illinois?) shouldn't be quite so quick to call others "dumb enough", just because they speak a bit differently from you. Even a non-American like me knows that:

a) Chicago doesn't have a governor (although Illinois does)
b) Obama has never been elected the governor of anywhere (or mayor for that matter), but was a state senator for Illinois and then a US senator
c) this is a site about English, which can be contentious enough without bringing politics into it, so can we keep politics out of it, please?

I've no doubt that somebody somewhere thinks you speak "funny" too. Most of us do to some other people. In Britain, every city has its own accent, but most of us don't criticise each other for that; we just see it as part of life's rich tapestry. How about a bit of "live and let live"?

I was wondering about what Ross Eiry was saying about there being many different myths with versions of heaven and hell. And I thought, yes, but these words surely have their roots in the Christian Heaven and Hell. But it turns out that both words seem to have existed in Anglo-Saxon before the Anglo-Saxons adopted Christianity.

Heaven apparently comes from Old English "heofon" - "home of God," earlier "sky, firmament," probably from Proto-Germanic

Hell comes from Old English "hel, helle" - "nether world, abode of the dead, infernal regions," from Proto-Germanic *haljo "the underworld"

(Online Etymology Dictionary)

Checking with Google Ngram, in the expressions: "go to heaven", "down from heaven" and "heaven-sent", lowercase predominates in published books, but something quite interesting happens: the gap between the instances of lowercase and uppercase versions was much higher in the nineteenth century than it is today.

http://books.google.com/ngrams/graph?content=to+heaven%2Cto+Heaven%2Cfrom+heaven%2Cfrom+Heaven&year_start=1800&year_end=2000&corpus=15&smoothing=3&share=

@Brus - demotic credentials? Is that something like street cred?

Seriously though, I'm glad you accept "Who wants to go? Not me!" and "She is taller than me."

I like your point about a disjunctive pronoun, but I'm not sure you can really say "me" is the equivalent of "moi", as we don't have a disjunctive pronoun in English. But "It's me" certainly sounds more natural in English.

Back to demotic credentials. Isn't it more to do with register than social status. To my friends at work, I might well say "Me and Dave are going to the pub", but to someone I want to impress or be more formal with, I'd say "David and I are going to the pub". But you might have a bit of a point in that in Britain, at least, language is "democratising". The use of the word "Mate" as a greeting, for example, which used to be exclusively working class, is pretty classless nowadays. What I do find fascinating is that it's almost always "Me and Dave" or "David and I", but hardly ever "Dave and me" or "I and David".

As I've probably said before, pronouns are the last area of English to have inflections, so it's hardly surprising if their use is still in a bit of a flux. We only have to look at "who/whom".