I saw a few bits here and elsewhere on it, but I have yet to find something
that explains its usage, in detail(e.g. in positive and negative contexts and
in different tenses). Anyone know?
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2016-05-03T22:49:30.133
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grammar
What's the grammar behind どうせ?
It only means "either way", "anyhow", "anyway", etc with a _fatalist_ nuance,
hence it can sound negative for some.

You can find it as other forms like どっちにしろ or どっちにせよ.
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2016-05-04T04:46:25.787
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While I'm sure the underlying grammar makes the analogy a rather liberal one,
I have always tended to feel that these were similar to patters in English
that use "be". That is, an old form of the subjunctive:

Ａであれ、Ｂであれ、なんでもいい。  
Be it A, or be it B, it's fine regardless.

どっちにせよ  
Whichever it be.

なんせ  
Whatever the case be.

The pattern can always (well, usually) be reworded using も to mean essentially
the same thing.

Ａでも、Ｂでも、なんでもいい。  
どっちにしても  
なんせ* (no strict conversion; maybe 何が何でも)
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2016-05-04T20:04:17.217
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> 今行ってもどうせ遅いので、行かないことにします。  
>  Since it is late to go now, I decided not go anyway.

It is similar to "anyway". But, you should use "douse" in negative context
only.
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2017-01-02T23:35:30.527
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