In other words:
I'm asking about how to efficiently signal actual pacifism.
And the best way to do that is:
Replace "serious injury or death" with "causing serious injury or death".
Still true conditioning on what you said. It remains true regardless of whether you're faking or not. That's why I didn't mention sincerity at all.
Based on my priors, if the draft board functions in a similar manner to typical american public boards and committees, then the general feeling and impression that the members of the board "get" of you will be 90% of the decision, assuming you have no record of violence and no obvious thing signalling that you don't actually believe in pacifism. The stronger their feeling(s), the more their mind will rationalize towards perceiving you as the kind of person you want them to perceive you as.
Thus, using a bit of Dark Arts by signalling first and foremost that you care only about minimizing violence throughout the world in all situations is an effective way to get their impression of you to reflect your actual views (given the assumptions).
It is not the only way, and it might not be sufficient on its own, but just that alone is enough to get me a job from an interview despite massive deficiencies in my resume over some other applicant who is clearly perfectly qualified and has exactly what they ask for.
Suppose that you believe larger scale wars than current US military campaigns are looming in the next decade or two (this may be highly improbable, but let's condition on it for the moment). If you thought further that a military draft or other forms of conscription might be used, and you wanted to avoid military service if that situation arose, what steps should you take now to give yourself a high likelihood of being declared a conscientious objector?
I don't have numbers to back any of this up, but I am in the process of compiling them. My general thought is to break down the problem like so: Pr(serious injury or death | conscription) * Pr(conscription | my conscientious objector behavior & geopolitical conditions ripe for war) * Pr(geopolitical conditions ripe for war), assuming some conscientious objector behavior (or mixture distribution over several behaviors).
If I feel that Pr(serious injury or death | conscription) and Pr(geopolitical conditions ripe for war) are sufficiently high, then I might be motivated to pay some costs in order to drive Pr(conscription | my conscientious objector behavior) very low.
There's a funny bit in the American version of the show The Office where the manager, Michael, is concerned about his large credit card debt. The accountant, Oscar, mentions that declaring bankruptcy is an option, and so Michael walks out into the main office area and yells, "I DECLARE BANKRUPTCY!"
In a similar vein, I don't think that draft boards will accept the "excuse" that a given person has "merely" frequently expressed pacifist views. So if someone wants to robustly signal that she or he is a conscientious objector, what to do? In my ~30 minutes of searching, I've found a few organizations that, on first glance, look worthy of further investigation and perhaps regular donations.
Here are the few I've focused on most:
Center on Conscience and War
Coffee Strong
War-Resister's International
The problems I'm thinking about along these lines include:
I'm curious if others have thought about this. Good literature references are welcome. My plan is to compile statistics that let me make reasonable estimates of the different conditional probabilities.
Addendum
Several people seem very concerned with the signal faker aspect of this question. I don't understand the preoccupation with this and feel tired of trying to justify the question to people who only care about the signal faker aspect. So I'll just add this copy of one of my comments from below. Hopefully this gives some additional perspective, though I don't expect it to change anyone's mind. I still stand by the post as-is: it's asking about a conditional question based on sincere belief. Even if the answer would be of interest to fakers too, that alone doesn't make that explanation more likely and even if that explanation was more likely it doesn't make the question unworthy of thoughtful answers.
Here's the promised comment:
Stated another way: