The Constitution means what it says. It doesn't necessarily mean what you want it to say.
It says "No ex post facto Law," which was a technical legal term that had a well-established legal meaning in 1789.
>It says “No ex post facto Law,” which was a technical legal term that had a well-established legal meaning in 1789.
Please expound and explain that then. Also be sure to include why the translation [of] “after the fact” is generally inappropriate.