The new tax bill will almost certainly take effect on 1/1/19 and apply to taxes from 2018. It hasn’t even been passed yet. It still has to go to a house senate conference committee to work out the differences in the bill and go to the President for signature. The IRS could not makes the changes necessary to implement the new law in 3 months much less a few weeks. I doubt it would even be legal to make ex-post facto changes in the tax law that would apply to 2017.
I don’t know if the ex-post facto rule in the constitution applies to criminal laws only or civil laws too. I think it’s both. Anyone who files taxes quarterly let me know if the IRS is ready with everything on april first. As for California, the constitution says, " congress shall make no law", not California .
Just think if you sold your house this year after owning for three years, you would be expecting to get 500k tax free. Then they change it to 5 out of 8 years. You would be very upset.
The constitution, at least where I came from, specifies that any law can’t go retroactively, and if it does, only if it is to benefit “we the people”. That’s the reason they don’t want to legalize marijuana. It would free those felons sent to prison for marijuana related cases.
It also, would prohibit the system to punish anybody, say, for spitting on the ground, if that event happened minutes or hours before the law was enacted.
I forgot what I learned about any law being debated in congress, but usually is published for experts, people and whatnot do give an opinion of the facts, then debated, which is not happening, then, voted on, and then published as a law, which then will become a law after certain time, I think 6 months later. Google it, it’s midnight, I am writing in the dark.