> One of the foundations of law that you cannot make retroactive changes.
This is a common misconception, at least regarding laws in the US. While I may not agree with it, the US Supreme Court has for literally centuries (like since 1798) explicitly allowed all types of retroactive laws. Most importantly, the USSC has long held the prohibition against ex post facto laws only applies to criminal, not civil laws. (As an aside, this also shows what bullshit it is when justices say they are just "calling balls and strikes". Justices, of all political stripes, make up laws all the time. The Constitution, as written, very clearly and plainly says "No Bill of Attainder or ex post facto Law shall be passed." At some point - Calder v. Bull in 1798 to be exact - the Supreme Court decided it only applies to criminal law.)
This is a common misconception, at least regarding laws in the US. While I may not agree with it, the US Supreme Court has for literally centuries (like since 1798) explicitly allowed all types of retroactive laws. Most importantly, the USSC has long held the prohibition against ex post facto laws only applies to criminal, not civil laws. (As an aside, this also shows what bullshit it is when justices say they are just "calling balls and strikes". Justices, of all political stripes, make up laws all the time. The Constitution, as written, very clearly and plainly says "No Bill of Attainder or ex post facto Law shall be passed." At some point - Calder v. Bull in 1798 to be exact - the Supreme Court decided it only applies to criminal law.)
Good info: https://www.law.cornell.edu/constitution-conan/article-1/sec... and https://supreme.justia.com/cases/federal/us/219/140/