When is a health care provider "forced" to kill?

I agree with Richard that we need to have nuanced, substantive conversations about conscience claims when crafting conscience protections.  Too often, "conscience" is invoked as some sort of trump card -- a "black box" that we must either accommodate or refuse to accommodate categorically, without being able to draw any distinctions among its claims.  At the same time, I fear that policy makers will more likely draw those distinctions based on political influence (exempting communion wine during prohibition, but not peyote during the war on drugs), rather than on the centrality of the particular belief to the believer. 

I also agree that forcing someone to kill what she thinks is an innocent human being strikes at the heart of conscience.  I would need a bit of clarification, though, about what we mean by "force."  Certainly if the government uses its coercive power to force me to kill, we're at the heart of what liberty of conscience must protect.  But what if I apply for the job of executioner, then ask to be relieved from the part of the job that involves killing?  Or what if I work as a doctor for Planned Parenthood?  What if I'm a pharmacist working at a university health center, where a huge portion of the revenue stream comes from various forms of birth control, including the morning-after pill?  Should our focus be on the employer forcing me to perform the part of my job description that, in my view, involves killing, or should our focus be on whether I am forced to hold this job in the first place?  Who should bear the burden of my conscience -- me (in the form, perhaps, of having to find a new job) or my employer (in the form, perhaps, of paying to have a second pharmacist on duty whenever I'm on duty, etc.)?  I don't claim to have easy answers here; again, I think we need a more nuanced conversation about conscience than the current culture war rhetoric contemplates.