As a libertarian I am opposed to abortion because I believe the life in utero is a unique individual entitled to full human rights. I also oppose capital punishment because I believe the powers of the estate should be limited; a prison sentence imposed in error can be compensated for, albeit imperfectly but a death sentence imposed erroneously cannot be corrected. One trip to the DMV will show the states propensity for error and unreason.
I think your position on capital punishment is reasonable and morally-defensible (although I don’t agree with it), but I’m curious - would you impose the death penalty on Tsarnaev if it was your call?
My “middle ground” on capital punishment would be to limit it to cases in which at least two of the following circumstances were fulfilled: that the perpetrator volunteered a confession that was not coerced; that the conviction was supported by incontrovertible physical evidence (DNA, fingerprints, videocam footage, etc); that the conviction was supported by at least two eyewitness accounts; and/or that the perp was convicted of more than one capital crime in more than one separate trial. Lots of room for legal fuzziness in those conditions, I realize, but hopefully the legal system could deal with those, and that sort of system would (I would hope) go about as far as one could to minimize death penalty mistakes.