Bismillah
Allahkabanda,
would you mind quoting from Quran and sunnah in favor of your POV.
yes, insha'Allah.The Messenger of Allah (sal-allahu alayhi wa salam) said: "It is not permissible to shed the blood of a Muslim who bears witness that there is no god except Allah and that I am the Messenger of Allaah, except in one of three cases: a soul for a soul (i.e., in the case of murder); a previously-married person who commits zina; and one who leaves his religion (Islam) and separates from the main body of the Muslims." [Sahih Al-Bukhari 6484; Sahih Muslim 1676]
The Messenger of Allah (sal-allahu alayhi wa salam) said: "Whoever changes his religion (Islam), put him to death". [Sahih Al-Bukhari 6922]
Death penalty for apostasy has been abolished, period.
talk about being a traditionalist; Allah says in the Qur'an (interpretation of the meaning): "Say: My Lord has only declared unlawful the obscenities, whatever is apparent from them and whatever is hidden, as well as sin, transgression without due right and that you associate with Allah that for which you have no authority, and that you speak about Allah without knowledge" [Surah al-A'raaf (7):33]
"And do not speak with that which your tongues describe falsely, 'This is lawful and this is unlawful,' so as to invent lies against Allah. Indeed, those who invent lies against Allah will never be successful. They will have a passing brief enjoyment, and they will have a painful torment" [Surah an-Nahl (16):116-117]
"Say: Do you see what Allah has sent down as sustenance? And you have made of it lawful and unlawful. Say: Has Allah permitted you, or do you invent a lie against Allah?" [Surah Yunus (10):33]
So Allah have said that they invent lies against Allah and they have no proof for it. Please keep your modernist heresies to yourself. May Allah protect us all from fitnah of people like you and evils of our tongues and guide us all to the straight path, ameen.
we're all in a position to understand
I am not too sure what you mean by that. I hope you are not referring to "being able to deduce rulings from the text".
Is there a distinction between treason and apostasy amongst classical jurists?
nope; no such distinction has been made because as the scholars have stated apostasy itself is a treason. Islam is a way of life and not just a spiritual religion.
Is such a distinction apparent by reading the Hadith?
nope, not to my knowledge. The text is pretty clear and there is an ijmaa among the sahabas (radiAllahu anhuma) as the scholars have mentioned it. Imam ibn Qudamah (rahimahullah) said: "(and the Prophet - peace and blessings of Allah be upon him - said: (whoever changed his religion, kill him), and the people of knowledge agreed unanimously on the obligatory of killing Al Murtad, and that had been narrated from Abi Baker, Umar, Uthmaan, Ali, Muaath, Abi Musa, Ibn Abbaas, Khalid and others than them, and that wasn't rejected so, it was an unanimous agreement" [Al Mughani(16/9)].
Has there ever been a case recorded in the Sunnah/Hadith of apostasy which was not committed during a time of war, for which a punishment was perscribed?
yes, number of cases; for example: 1 - The hadith of Jabir that a woman called Umm Marwaan apostatized from Islam, then the Prophet (sal-allahu alayhi wa sallam) gave an order to present Islam for her, if she comes back or she got to be killed' [Narrated in Sunan Al-Daarqutni (118/3), Sunan Al-Bayhaqi Al-kubraa (203/8)]
2 - And it is as narrated from Abu Musa and from it "'O Abu Musa! (or 'Abdullah bin Qays!) Go to Yemen'. The Prophet then sent Muaath bin Jabal after him and when Muaath reached him, he spread out a cushion for him and requested him to get down (and sit on the cushion). Behold: There was a fettered man beside Abu Musa. Muaath asked, 'Who is this (man)?' Abu Musa said, 'He was a Jew and became a Muslim and then reverted back to Judaism'. Then Abu Musa requested Muaath to sit down but Muaath said, 'I will not sit down till he has been killed. This is the judgment of Allah and His Apostle (for such cases)' and repeated it thrice. Then Abu Musa ordered that the man be killed" [Sahih Al-Bukhari (2537/6); Sahih Muslim (1456/3)]
3 - Abu Bakr (radiallahu anho) waged war against those who refuses to pay zakah and called it war on apostasy.
Cases or no cases is not that relevant when we come to know the understanding of the companions. We know that they made no distinction between treason and apostasy or said that treason is a condition for killing an apostate. Allhamdulillah, there is an ijmaa' which alone should be enough to cast away any dubious doubts.
Are scholars invoking abbrogation, or using inference, to suggest that apostasy outside the bounds of war is identical to apostasy within?
Apostasy has nothing to do with war per say but to answer your question some scholars did say that there is a major apostasy and there is a minor apostasy. They said that if an apostate wages/incites war against Muslims (by any mean) then he has committed major apostasy and he must be put to death even if he repents. As far minor apostasy, they said that he must be put to death if he doesn't repent but if he does then his repentance is accepted. Note that they didn't make difference between whether he is killed or not rather they made difference between whether his repentance is accepted or not.
and Allah knows best