I hate to admit it but I don't remember a problem with the Californian ballots. I guess I overlooked it while all the talk was going on about the ballots in Dade County, Florida.
Oops. Those American states all look alike to me.
I like the idea of this thread turning into a legit alternate history thread. Cheezy will throw a fit.
For the first one, I have to ask: how are the mechanics of this coming about? Are you planning to replace this with Mithraism or something? Because as far as I know - Plotinus would be a better person to ask about this, but I think he has some disdain for counterfactuals - the Greco-Latin polytheism, though still numerically dominant, was pretty much spent. For the second...I'm gonna go out on a limb here and say that it would not have had a macrohistorical effect.
Some pagan cults, such as Mithraism, were in decline by the fourth century, but Roman paganism in general was perfectly alive and well. To say it was "spent" raises the question what people were believing instead! In fact it was flourishing. Maximinus Daia, ruler of the eastern empire until Licinius defeated him in 313, sponsored a new and vigorous pagan cult in Antioch which was modelled, in structure, after the Christian church. This did very well until Licinius arrived, executed its high priest, and banned it.
Now paganism did fade after Christianity was legalised, because the Christian church took over such important functions in society. The
xenodocheia, for example, and the episcopal audience which Constantine established, ensured that the church in general and bishops in particular became very central to society. By the time of Julian, this had become an insurmountable obstacle to anyone hoping to restore paganism to its former position.
But the idea that paganism was just fading away before the Edict of Milan, and that Christianity naturally stepped into the breach is, I think, something of a Christian myth intended to avoid admitting that paganism only died out because the Christians went to enormous efforts to ensure that it did. In fact it was still doing pretty well even in the time of Justinian, which is why he enacted such extreme measures to try to stamp it out.
It's hard to imagine an alternate history in which the Roman empire never legalised Christianity. Apart from the Great Persecution of Diocletian and Galerius, there were no persecutions at all between Valerian in the 250s and the Edict of Milan. In fact the religion was effectively decriminalised as early as 306 or thereabouts in the western empire, not simply by Constantine but by Constantius I and also Maximus, and had been largely ignored by the authorities for most of the second half of the third century. So legalising it seems to have been a pretty natural thing for any Roman ruler to have done by the time of Constantine, whatever their own religious sympathies. What made the difference was that Constantine promoted it, meddled in its internal disputes such as the Donatist schism and the Arian controversy, and made it much more central to society in ways such as those mentioned above.
If these things had never happened, then Christianity would probably have turned out rather different. But I'm not convinced that history overall would have been so different, at least in Europe. After all, the Roman empire fell. The barbarians who inherited its territories were either already Christians anyway, or they later became Christians through the efforts of missionaries. Those who were Christians were Arians anyway, not Nicenes as the Roman Christians were by the time of the fall of the empire. So the subsequent history of Christianity in Europe would probably have happened anyway.
You might argue that if the Roman empire had never Christianised then Middle Eastern history would have been very different. Perhaps if the "True Cross" had not been in Jerusalem, the Persians wouldn't have made off with it, and if Heraclius had not been a Christian, he would not have been so concerned to get it back and devastate Persia in the process. And if that hadn't happened, perhaps the Arabs wouldn't have found the conquest of Persia so easy, in which case Islam would never have had the success it did. But this is getting into very speculative territory.