Understanding ~たのでは "Conditionals"


I recently came across a [sentence containing
~たのでは](https://japanese.stackexchange.com/questions/101207/understanding-%e5%bf%83%e8%87%93%e9%ba%bb%e7%97%ba%e3%81%a3%e3%81%a6%e6%ad%bb%e5%9b%a0%e3%81%8b%e3%82%89%e6%b4%97%e3%81%a3%e3%81%9f%e3%81%ae%e3%81%a7%e3%81%af-%e4%bd%95%e3%82%82%e5%87%ba%e3%81%be%e3%81%9b%e3%82%93%e3%81%8b%e3%82%89%e3%81%ad/101211#101211)
I found quite hard to parse, and I wanted to focus more on just its ~たのでは
aspect to make a more focused question.

So consider:

> 「彼が **来なかったのでは** 、何も始まらない。」

It seems like the best way to parse this sentence is as a conditional:

> **Idiomatic Translation:** If he doesn't come, nothing will start.

**Questions:**

  1. Is this sentence _literally_ a conditional, or are English speakers just translating it as one to help make sense of it?

> **Literal Translation(?):** As for (は) it being the case that (の) he didn't
> come, nothing starts.

  2. Does ので in these conditionals have anything to do with the ので which is a (more formal) synonym of から?

  3. Why is 来る in the past tense, as opposed to the present tense (来ないのでは) or て-form (来なくては)?

  4. If this sentence really is a conditional, how does it compare to the various other conditional forms it could be expressed as? Here's my attempt:

    1. **~たら.** 「彼が **来なかったら** 、何も始まらない。」 "If he didn't come, nothing will start." (Places emphasis on the willful action of the person coming or not?)

    2. **~と.** 「彼が **来ないと** 、何も始まらない。」 "If he doesn't come, nothing will start." (Almost as if it were a scientific law; sounds weird or hyperbolic in most situations?).

    3. **~えば.** 「彼が **来なければ** 、何も始まらない。」 "If he doesn't come, nothing will start." (Not as strong as (2), but still stated more as a dispassionate evaluative or hypothetical fact, and de-emphasizes the act of coming or not as a willful action?)

    4. **のでは.** 「彼が **来なかったのでは** 、何も始まらない。」 "If _it's the case_ he didn't come, nothing will start." (places emphasis on "if it's the case case that.." (の)?)

