Thematic and meta-textual arguments first
- This is the most absurdly heavy-handed strawman choice of moral non-dilemma I have ever seen. There is no subtlety here. There is no nuance here. There is just a cartoonishly evil side, and heroic opposition. There are some counterarguments that can be made about "necessity" and I'm going to demolish them, because there are many ways to do similar things that aren't nearly as ridiculous.
- You chose to treat an extremely sensitive moral issue with flippancy. Describing "abortion pills" being put in every sort of food and drink trivializes it as a joke, and repeating it for effect continues that. That isn't how this sort of order would be implemented, and the absurdity of it can't realistically be interpreted in any way but as a joke.
- Inverting the typical abortion debate by discussing enforced abortion, or sterilization, creates a huge amount of moral dissonance. It violates bodily autonomy even moreso than the anti-abortion position, which pairs poorly with being used for a cheap laugh. Thematically, you're saying "no one in the US cares about the issue of abortion on any sort of moral level", because this mortally offends both sides at the same time. While this may be a reasonable level of cynicism about politicians, it stretches suspension of disbelief.
I will take a brief break here to say that you could approach this less offensively by threatening something like... coerced hysterectomy, or similar contraceptive procedure, before pregnancy, as they became aware of fraternization, just to prevent this sort of situation. These are still all morally horrifying, and invoke the same issues of bodily autonomy and consent, but can be treated seriously. "We're sneaking abortion pills into your food" is just tasteless. Also, these alternatives do a similar job of being paternalistically "we know what's best", but can also be reasonably spun to the public, and aren't nearly as likely to get shipgirls offended enough to kill you. They're more morally grey options, because they seem like reasonable and pragmatic ways to prevent this exact situation, which is political (and literal) suicide.
Now the political:
- This isn't even the role of the legislative branch. They don't have the legal authority to take this sort of action. You even call this out, that they aren't in the chain of command. They could pass legislation sent up from the House declaring shipgirls as having no rights (though that would probably get challenged in court immediately). They can't order around the military, they can't give themselves "emergency powers". Those would go to the President. That's the role of the executive branch, to make decisions quickly. The Senate is a SLOW branch of government.
- If the Joint Chiefs of Staff and President refuse to enforce disciplinary actions, in a state of emergency, the Senate can't really do anything about it in the short term. There's no reason for soldiers to follow their orders.
- If the Joint Chiefs of Staff and President are willing to enforce disciplinary action, there's no reason to go to the Senate. This is dereliction of duty, insubordination, or mutiny, and shouldn't go that high in the chain of command. This would be dealt with via court-martial. In a typical real-world case, this would result in dismissal and censure, but it's fairly obvious that in this setting, shipgirls are essentially "national weapons", and dismissal, summary execution, or censure aren't options because they are needed for combat.
And world building:
- It seems enormously unrealistic that this world treats shipgirls as non-persons. When did shipgirls first appear? How did they appear? It seems like they, and Abyssals, are relatively recent arrivals into this world, so there's not substantial reason for the world's culture to differ from ours before that divergence point. There is no sane world in which the US government encounters an enormously powerful, autonomous, intelligent being who is willing to help them, says "ah, you are a slave and non-person", and then intentionally pisses them off with no defensive measures. The balance of power is completely wrong. If every nation had something similar to the "Fleet brand" we saw before, which could be used to enforce compliance or something similar from the chain of command, this might make sense. But they don't, so it's just immersion-breakingly, cartoonishly stupid. You aren't disarming them, you aren't even doing something somewhat intelligent like the dead Japanese admiral by threatening their loved ones to neutralize them, you're just calling them over, while they're armed, and relying on their goodwill? Loyalty? for them to not kill you as you abuse them.
- It's clear they recognize shipgirls are extremely powerful and important, because they're treated as national weapons.
- It's clear they recognize shipgirls are autonomously intelligent, or they wouldn't bother to "hint"
- On that note, the military does not "hint". The Senate does not "hint". "Are you not willing to follow the hints of the US Senate, for your own good?" is one of the most discordant sentences I have read in weeks. No politician would phrase it like that. It's undignified. By the time you would have this sort of hearing, there would be explicit orders in writing already. The admirals would have received orders to pass on, and the shipgirls would be reassigned. If the admirals weren't willing to enforce those orders, they would be the targets of discipline, which would be much more effective, because shipgirls seem to be emotionally attached to their admirals, and killing soldiers sent to arrest a mutinous admiral would at least happen at a safe distance for the politicians, if they absolutely insisted on forcing this sort of conflict (which I will reiterate, is stupid to do)
- I'm vaguely annoyed that it's not known (or at least, not stated) if the offspring of shipgirls and humans are merely human, or possibly also shipgirl. I suppose at the moment the intensity of the conflict makes that a non-factor, but it would add a bit to the callousness of the government position, and highlight the pragmatism of it.
So yeah, there are about half a dozen reasons off the top of my head why this should never happen this way. If I add some assumptions that haven't been shown in this setting, I can make some parts seem more reasonable, but others become even worse.
Let's imagine that shipgirls become significantly more effective in combat, in a demonstrated way, when commanded by someone they have emotional attachment to. This incentivizes the military to promote fraternization (sexy admirals). This also has the obvious effect that the emotional state of shipgirls and their admirals would be considered paramount, so they would be given VIP treatment, not passed over and abused. This would also lead decision makers to immediately be concerned with proactive contraceptive measures, if pregnancy is predictable and also renders shipgirls not combat-ready.
Even if there isn't massive direct combat benefit, but the military is just rationally considerate of the feelings of the sentient weapons that are choosing to help them, they would still have pregnancy concerns at an earlier stage. Of course, "being rationally considerate of the feelings of sentient weapons" is at obvious odds with what happens in this scene, and again, if the military chooses to do something during wartime, the Senate doesn't get to overrule them except through legislative process.
If we instead suppose that the Senate has somehow done some sort of
coup d'etat and now runs the government directly, I think that would be utterly ridiculous. They don't have the support of the military, evidently. They're the least decisive and least efficient body to make executive decisions available. Remember how last chapter, the Emperor in Japan is more important, because unitary executive power is useful for dealing with a crisis? This is the exact opposite of that.
If the situation was that the JCS had overthrown the President and was ordering this, and the US is now a military dictatorship,
sure, that's very reasonable, but then you're not dealing with the Senate, or "politicians", and the military would probably have a much more realistic threat assessment of the dangers posed by angry shipgirls.
If the Senate has confirmed legislation stripping shipgirls of rights with a veto-proof majority, and has the support of the military in enforcing it, there is still no reason for them to have this direct confrontation, on so many levels. They're doing the equivalent of bringing a man to trial without any guard, not handcuffed, and carrying a fully automatic weapon plus some grenades, and telling them, in person, that they're being sent to a concentration camp. Why are we even patting down shipgirls for weapons? They evidently can't be disarmed! No. No. No realistic threat assessment would EVER DO THAT, and it absolutely destroys my suspension of disbelief.
The only way that makes sense is if the military or executive branch just wants to wipe out this half the Senate, and is deliberately misadvising them about the level of danger to get them killed. Which... is plausible, particularly in 2013, but I had to contort myself so hard to find that possibility that I can't give it credence as being intended, and it would require considerably more foreshadowing to be remotely satisfying. It also has nothing to do with the stated reasons for the scene.
It is around this point that I realize that I shouldn't be quite this level of annoyed, and this is probably has a very harsh tone. Sorry about that, but I really think that scene could be done better.