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I find it difficult to distinguish between due to and because of. They carry the same meaning to me which is cause and effect.

Here's an example that requires because of.

Because of public pressure, national leaders have been holding talks in hopes that they can come up with global solutions

An example of due to

In the past six years, the Tribe has always requested additional funds to assist the students that were being denied due to lack of funds

I find them interchangable. Emotion: sad

What do you think?

Thanks!
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Because = on account of
Due to = relating to the cause
I'm not going because nobody invited me. (on account of the fact that nobody invited me)
I'm not going due to lack of funds (the cause of my not going is lack of funds)
I'm not going because I don't like him - gives us the reason why I'm not going
I'm not going due to not liking him. (not a good sentence really - but the meaning is - due to the fact that I don't like him - so we have the cause)
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I don't quite understand on account of...sorry for making your job more difficult.

But in your first example, no invitation sounds like a cause to me. As a result of not having an invitation, I can't go, therefore, I'm not going. Emotion: sad
I think I'm trying to distinguish between reason and cause.
Having no invitation is the reason I am not going. - because nobody invited me.
The fact that nobody invited me is also the cause of me not going - due to not having been invited.
New2grammar
In the past six years, the Tribe has always requested additional funds to assist the students that were being denied due to lack of funds

According to English usage books, you should use 'due to' with a noun. You should use 'owing to' in the above sentence.

The accident was due to reckless driving.
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