How to parse 政治家にあるまじき発言?

Question

Consider the following sentence:

その大臣は政治家にあるまじき発言で、辞任に追い込まれた。

I would like to know in particular how the section in bold should be parsed. For example:

• Since まじき is the attributive form of まじ, does まじき bind to 発言?
  • eg: 政治家にある［まじき発言］
• Alternatively, does ある bind to まじき first?
  • eg: 政治家に［［あるまじき］発言］
• Or is it that the whole left side be attached together?
  • eg: ［政治家にあるまじき］発言
  • And if so, is it ［政治家にある］まじき, or 政治家に［あるまじき］? Or...?

My bet right now is on 政治家に［あるまじき］, since まじ is an auxiliary verb. In this case, it is an auxiliary for ある, therefore I think that まじき makes あるまじき an attributive form as a whole. However, I'm not sure what exact role に plays in this interpretation.

Answer 1

まじ is an auxiliary verb in archaic Japanese. When you read archaic Japanese, you have to understand how まじ conjugates, including its attributive form まじき. In modern Japanese, まじ is no longer actively used, except that negative-volitional まじ in 終止形 is occasionally used in place of まい in stiff literary works (e.g. 我らも遅れまじ "we ought not drop behind"). But あるまじき has survived as a fixed set phrase meaning "unbecoming" or "(ethically) inappropriate", and it's still relatively common. Basically you can treat あるまじき as a fossilized 連体詞 (attributive). Dictionaries of modern Japanese usually have a dedicated entry for あるまじき.

It takes に or として, and ～ + (に/として) + あるまじき means "(which is) inappropriate for ～" or "unbecoming to ～". So 政治家にあるまじき発言 is parsed like ［［政治家に→］あるまじき→］発言, "a statement which is inappropriate for a politician."

Answer 2

あるまじき is listed in the dictionary as one single expression.
It means "inappropriate", "absurd", "unacceptable", "inconvenient".

あるまじき【有るまじき】［連語］《動詞「あり」の連体形＋打消し推量の助動詞「まじ」の連体形。連体詞的に用いる》あってはならない。不都合である。とんでもない。「指導者に有るまじき振る舞い」
https://dictionary.goo.ne.jp/jn/7932/meaning/m0u/有るまじき/

So the sentence becomes:
政治家にあるまじき発言
A statement inappropriate for a politician (to say)

Answer 3

その大臣は政治家にあるまじき発言で、辞任を追い込まれた。

I'm not quite sure I understanding the parsing question, but I take the sentence to mean:

The minister's statement was, considering that he's a politician, shocking enough that he was driven into retirement.

To arrive at this, I'm working from the following:

1 . ... 発言で、追い込まれた　- "because of statement was driven into retirement"

2. その大臣は...発言で、追い込まれた。 "that minister was because of statement drive into retirement"
3. その大臣は...まじき発言で、追い込まれた。 - "that minister was because of unbelievable statement driven into retirement" (working from definition 5 from 大辞林 第三版の解説)
4. その大臣は 政治家にある　まじき発言で、追い込まれた。 "that minister was because of unbelievable for a politician statement driven into retirement"

and then fixing it up in the English.

At least that's how I parse it.