>>12577602The fact that populations get less religious matter. It does.
But, what also matters is that religious people decides their vote based on the religious beliefs of candidates more often than non religious peoploe do that.
It is more common for a christian to care if the candidate is christian, or for a jew to care if the candidate is jew, or a muslim to care if the candidate is muslim (or whatever the religion) than it is for a non-religious person to care if the other guy is non-religious.
And that second effect still surpass the decline of religion beliefs in the population.
You can actually get elected just by being "the catholic/jew/muslim (or whatever) guy from that district".