Against.
Abortions should be safe and legal, regardless of method, unless there are exceptionally strong reasons for the WA/state to assert medical judgment on these matters. The proposal at hand gets medical facts wrong, and bans many procedures that do not even resmeble what it is trying to ban. It discriminates between legitimate abortion methods, even though this particular one may in fact be medically necessary in some cases.
Notably, there isn't even a requirement for viability here. Further, the definition of
birth not only is not medically accurate (it is internally inconsistent), but does not seem to distinguish between a complete delivery (that is, the fetus being entirely outside of its mother) and a mere small part of it being outside of the uterus.
This means that an abortion which involves some delivery out of the uterus of any extent, at any stage of the pregnancy, is prohibited.
The resolution claims that these procedures are "needlessly bloody but also dangerous". There is no evidence for this. Further, it claims that these procedures are never "medically necessary". Again, the evidence is simply not there. An abortion may be necessary to save the woman's life, and a partial delivery may be the only safe method to perform it. For a medical judgment of necessity to be made by the WA in the negative in absolutely all cases would be astonishing.
Astonishingly, after claiming that this operation is never medically necessary, the proposal goes on to make medical necessity an exception to prosecution. (The requirement to "duly prosecute" in itself is also a gross breach of the prosecutorial discretion that WA member states would want to uphold, and amounts to micromanaging the prosecutorial process.)
Another false claim passed off as "fact" is that at the time of birth, the fetus is necessarily "well-developed". Given that these types of abortions are at times performed as early as 16 weeks, well before viability, this claim doesn't really help the proposal's already abysmal record on getting the facts right.
For a technical discussion on 'partial-birth abortion', one cannot go past
Stenberg v. Carhart, which deals directly with some of the factually incorrect material the authors attempt to import as medical 'facts'.
Finally, as one last trick up its sleeve, the proposal somehow claims that it does not interfere with the right to an abortion. I thought I could not be any more incredulous, but here I am.