I respectfully disagree. If anything our current polarized political environment and what you could either call populous or mob rule, depending on how charitable you are feeling, makes it easy to imagine a set of circumstances where a person would be wrongly convicted of a capital crime.
In the last year I have seen people involved in protests, counter protest or defending themselves from rioters (depending on your perspective) accused of murder, attempted murder, and insurrection, both in washington state and washington d.c.
Just as in past examples of racially motivated unjust prosecution, it remains only possible to make amends for such an injustice so long as the person is still alive. I see no reason our fallible justice system or government needs the final sanction of execution. The work of groups like the innocence project make it clear just how often the system gets things wrong.
Moreover, I think this is a position that people on both sides of the current political spectrum should see as reasonable.