Ethics of Oppenheimer
Sources from Rabbi Alex's lecture "The Ethics of Oppenheimer" on human dignity, pikuach nefesh, self-defense, and war.

(ב) וַתֵּ֥צֵא אֵ֛שׁ מִלִּפְנֵ֥י יְהֹוָ֖ה וַתֹּ֣אכַל אוֹתָ֑ם

...וַיִּדֹּ֖ם אַהֲרֹֽן׃

(2) And fire came forth from יהוה and consumed them...
And Aaron was silent.

(כז) וַיִּבְרָ֨א אֱלֹהִ֤ים ׀ אֶת־הָֽאָדָם֙ בְּצַלְמ֔וֹ בְּצֶ֥לֶם אֱלֹהִ֖ים בָּרָ֣א אֹת֑וֹ זָכָ֥ר וּנְקֵבָ֖ה בָּרָ֥א אֹתָֽם׃
(27) And God created humankind in the divine image,
creating it in the image of God—
creating them male and female.

לֹ֥֖א תִּֿרְצָ֖͏ֽח...

You shall not murder...

שנים שהיו מהלכין בדרך וביד אחד מהן קיתון של מים אם שותין שניהם מתים ואם שותה אחד מהן מגיע לישוב דרש בן פטורא מוטב שישתו שניהם וימותו ואל יראה אחד מהם במיתתו של חבירו עד שבא ר' עקיבא ולימד וחי אחיך עמך חייך קודמים לחיי חבירך

If two people were walking on a desolate path and there was a jug [kiton] of water in the possession of one of them, and the situation was such that if both drink from the jug, both will die, as there is not enough water, but if only one of them drinks, he will reach a settled area, there is a dispute as to the halakha. Ben Petora taught: It is preferable that both of them drink and die, and let neither one of them see the death of the other. This was the accepted opinion until Rabbi Akiva came and taught that the verse states: “And your brother shall live with you,” indicating that your life takes precedence over the life of the other.

לפיכך נברא אדם יחידי ללמדך שכל המאבד נפש אחת מישראל מעלה עליו הכתוב כאילו איבד עולם מלא וכל המקיים נפש אחת מישראל מעלה עליו הכתוב כאילו קיים עולם מלא

Therefore, Adam the first man was created alone, to teach you that with regard to anyone who destroys one soul from the Jewish people, i.e., kills one Jew, the verse ascribes him blame as if he destroyed an entire world, as Adam was one person, from whom the population of an entire world came forth. And conversely, anyone who sustains one soul from the Jewish people, the verse ascribes him credit as if he sustained an entire world.

ומפני שלום הבריות שלא יאמר אדם לחבירו אבא גדול מאביך ושלא יהו המינים אומרים הרבה רשויות בשמים
The mishna cites another reason Adam the first man was created alone: And this was done due to the importance of maintaining peace among people, so that one person will not say to another: My father, i.e., progenitor, is greater than your father. And it was also so that the heretics who believe in multiple gods will not say: There are many authorities in Heaven, and each created a different person.
גמ׳ אמר רבא מאי טעמא דמחתרת חזקה אין אדם מעמיד עצמו על ממונו והאי מימר אמר אי אזילנא קאי לאפאי ולא שביק לי ואי קאי לאפאי קטילנא ליה והתורה אמרה אם בא להורגך השכם להורגו
GEMARA: Rava says: What is the reason for this halakha concerning a burglar who breaks into a house? He explains: There is a presumption that a person does not restrain himself when faced with losing his money, and therefore this burglar must have said to himself: If I go in and the owner sees me, he will rise against me and not allow me to steal from him, and if he rises against me, I will kill him. And the Torah stated a principle: If someone comes to kill you, rise and kill him first.

(ו) בַּמֶּה דְּבָרִים אֲמוּרִים בְּשֶׁעָבַר וְעָשָׂה הֶעָוֹן שֶׁחַיָּב עָלָיו מִיתַת בֵּית דִּין. אֲבָל הָרוֹדֵף אַחַר חֲבֵרוֹ לְהָרְגוֹ אֲפִלּוּ הָיָה הָרוֹדֵף קָטָן הֲרֵי כָּל יִשְׂרָאֵל מְצֻוִּין לְהַצִּיל הַנִּרְדָּף מִיַּד הָרוֹדֵף וַאֲפִלּוּ בְּנַפְשׁוֹ שֶׁל רוֹדֵף:

Every Jew is commanded to save a person being pursued for his life, even if it means killing the pursuer, and [even if] the pursuer is a minor. Thus, if warning is issued and he continues to pursue, the pursuer can be killed even without his acknowledging the warning. But if the pursuer can be stopped by disabling part of his body, by striking him with an arrow, a stone, or a sword...then that should be done. And this is a negative commandment: not to have mercy on the life of a pursuer.

דְּאָמַר רִבִּי שְׁמוּאֵל בַּר נַחְמָן שָׁלֹשׁ פרסטיגיות שָׁלַח יְהוֹשֻׁעַ לְאֶרֶץ יִשְׂרָאֵל עַד שֶׁלֹּא יִכָּֽנְסוֹ לָאָרֶץ מִי שֶׁהוּא רוֹצֶה לְהִפָּנוֹת יְפַנֶּה. לְהַשְׁלִים יַשְׁלִים. לַעֲשׂוֹת מִלְחָמָה יַעֲשֶׂה.

For Rebbi Samuel bar Naḥman said, Joshua sent three orders to the Land of Israel before they entered the Land: Those who want to evacuate should evacuate, those who want to make peace should make peace, those who want to go to war should go to war.

(יט) כִּֽי־תָצ֣וּר אֶל־עִיר֩ יָמִ֨ים רַבִּ֜ים לְֽהִלָּחֵ֧ם עָלֶ֣יהָ לְתׇפְשָׂ֗הּ לֹֽא־תַשְׁחִ֤ית אֶת־עֵצָהּ֙ לִנְדֹּ֤חַ עָלָיו֙ גַּרְזֶ֔ן כִּ֚י מִמֶּ֣נּוּ תֹאכֵ֔ל וְאֹת֖וֹ לֹ֣א תִכְרֹ֑ת.

(19) When in your war against a city you have to besiege it a long time in order to capture it, you must not destroy its trees, wielding the ax against them. You may eat of them, but you must not cut them down.

(ז) כשצרין על עיר לתפשה אין מקיפין אותה מארבע רוחותיה אלא משלש רוחותיה ומניחין מקום לבורח ולכל מי שירצה להמלט על נפשו

(7) When a city is sieged to be conquered, we do not surround the four sides of it , rather, only three, and a place is selected as a place where whoever wants to flee and save their lives can

The price [of war] is also paid by the enemy, who is also graced with the Divine image, and one should grieve whenever God's creations drown in the sea. On this point, the issue of quantity is meaningful, and one certainly must weigh the justifications for harming many in order to save an individual.
Rabbi Aharon Lichtenstein, Ethics and War, Techumin 4, pg. 184-5
ואמר רבי יוחנן מאי דכתיב (שמות יד, כ) ולא קרב זה אל זה כל הלילה בקשו מלאכי השרת לומר שירה אמר הקב"ה מעשה ידי טובעין בים ואתם אומרים שירה
And similarly, Rabbi Yoḥanan said: What is the meaning of that which is written: “And the one came not near the other all the night” (Exodus 14:20)? The ministering angels wanted to sing their song, for the angels would sing songs to each other, as it states: “And they called out to each other and said” (Isaiah 6:3), but the Holy One, Blessed be He, said: The work of My hands, the Egyptians, are drowning at sea, and you wish to say songs? This indicates that God does not rejoice over the downfall of the wicked.
תאני רב יוסף מאי דכתיב (שמות יב) ואתם לא תצאו איש מפתח ביתו עד בקר כיון שניתן רשות למשחית אינו מבחין בין צדיקים לרשעים
Rav Yosef taught: "What is the meaning of the verse: 'None of you shall go outside the door of his house until morning' [Exodus 12:22]? Once permission has been given to the Destroyer, it does not differentiate between righteous and wicked.
"I remembered the line from the Hindu scripture, the Bhagavad Gita; Vishnu is trying to persuade the prince that he should do his duty, and to impress him, takes on his multiarmed form and says, ‘Now I am become Death, the destroyer of worlds.’ I suppose we all thought that, one way or another.”
-J. Robert Oppenheimer