Agreed. Although, rape stopped being a
capital crime in the UK in 1841, so any government wanting to reintroduce it for that would have to be right-wing nutters.
I take it that you haven't been following the current mob?
But back on the subject of deterrence, the death sentence isn't one. It has never been one. In the days of the Bloody Code you could be hanged for picking a pocket. It was observed by more than one person that as the previous tranche of pick-pockets were doing the air dance, there would be more in the audience working their trade. It doesn't work for murder for reasons that ought to be obvious, but I'm going to spell out anyway. It's because murders fall into these categories:
1) Spur-of-the-moment. These people only formed the intention to kill seconds before committing the offence. They never thought about possible punishment, so how could it deter?
2) Planned. These people plan not to be caught, so a punishment that they don't believe they will get cannot deter.
3) Nothing to lose. This is drug dealers and the like. They are aware that they are likely to die young anyway.
4) The genuinely mad. They don't make rational decisions, so don't think about punishment.
5) Want to die. Mainly religious fanatics and the like. Martyrdom is their aim - why should we help them recruit others?
As for other crimes, there's little evidennce that any particular punishment deters them. Not least because so few are caught. Why would a (say) burglar care about death for his crime given the tiny chance he will be caught. And as others have pointed out, as soon as you add death as a penalty for any crime less than murder, you incentivise the crim to murder any witnesses.
Then there's the "100% solid evidence" idea. It's rubbish. There has probably been about three murders in all of this country's history that fall into this category. This is mainly a sop that pro-DP throw to try to trick anti-DP people. And also, how quickjly do you think that 100% would become 99%? 90%? Pretty much as soon as the next murder of a either a child or a young white woman. There WILL be innocent people executed. Absolutely and without question.
Finally, let's look at the logic. The state is saying: it's wrong to kill. And to prove this, we are going to kill you.".