The problem with this proposal is that the State would have to adopt an official religion. We have already seen that in those nations where the State has an official religion there are abuses or eventually the religion is ignored, because enforcement becomes impossible.
Islam: those nations where Islam is the official religion of the State have serious problems in the area of human rights. Also, in those states, the government only protects the rights of Islam, Christians and others have no religious rights in these nations.
Judaism: in Israel Judaism is the State religion. To protect Judaism they have had to pass laws that make us cringe. For example, an Israeli Christian cannot hold public office. Israel does a fairly good job protecting the holy sites of Judaism, Islam and Christianity. They also allow Christians and Muslims to worship. But they do not allow Israeli Christians and Muslims to participate in public affairs. In addition, people like me, lose our right to participate in public affairs.
I was born Jewish and converted to Catholicism. This makes me a heretic. This is interesting; because I’m still a Jew, a Catholic Jew, but a Jew nonetheless. Even if you become an atheist, you’re a Jew because you were born to a Jewish mother. It’s like being Irish Catholic and Irish. The point is that the State treats you as a heretic if you convert, but if you’re an atheist, you’re still in good standing with the State, because you have not defected from the faith. You never had faith to begin with.
Anglicanism: the UK has an official state religion. In the end, they have had to ignore their own rules. There was no way the nation was going to progress unless they accepted Hinduism in India, Catholicism in their American colonies and Islam in Palestine when they held the reigns. At the same time, the Prime Minister must belong to the Church of England, at least nominally. Tony Blair came out of the Catholic closet after he left office.
I don’t see any way that the State can define blasphemy unless it adopts a state religion. We know that the Catholic Church will not accept being the official religion of the USA. No other religion has written and preached on freedom of religion for everyone as has the Catholic Church. I don’t believe there will be much support on this idea from that corner. I could be wrong.