If political expediency is the excuse, then lets look at why some Muslims believe in the death sentence for apostacy, given that its not defined in the religion.
Classical Hanafi doctrine holds that the capital punishment of the apostate serves mainly political aims. I quote two famous Hanafi jurists from Central Asia on this matter. The first is the eleventh-century Transoxanian jurist Sarakhsi, one of the major authorities of the Hanafi school. He says:
The change of religion and the original form of unbelief
belong to the most abominable of crimes. But [their judgment]
is a matter between God and his servant and the punishment
[of this crime] is postponed until the hereafter.
The measures advanced in this base world [and which thus
precede God's judgment] are matters of political expediency
[siyasat mashru'a] ordained by the law in order to protect
human interests" (Sarakhsi, n.d., vol. 10: 110).
In the same vein, the twelfth-century Hanafi jurist Marghinani, whose book al-Hidaya exerted a lasting influence on the Hanafi jurists of the Near East, states his position with the following words:
In principle, punishments are postponed to the hereafter
and the fact that they are advanced [so that they precede
the hereafter] violates the sense of probation [as the sense
of human life in this world]. One deviates from this principle
in order to defy a present evil and that is warfare
[against the Muslims] ('Ayni, vol. VI: 702-703). (2)
Both authors argue that the apostate's punishment is not due to his belief but to the military and political danger that this belief may cause. They use this argument to show that women, even if they abandon Islam, should never be condemned to death because they are, according to Hanafi doctrine, physically not able to lead war on the Muslim community. The jurists conclude from this that capital punishment is not imposed for disbelief and apostasy but as a means to prevent the military and political dangers connected with it.
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