California has been trying to ban the delicacy foie gras for quite some time. The French dish is well-known in fine dining, but it is made from the liver of a duck or goose that has been force-fed to increase the fat content. Many have said the process constitutes animal cruelty.
The ban was passed into law back in 2004, but it was phased in gradually. It finally went into full effect in 2012, at which time foie gras producers promptly sued the state government. Fast forward to 2015, and a federal judge overturned the ban, stating that it was unconstitutional and went against federal poultry law.
Two years after that, the higher Ninth Circuit court ruled 3-0 that the federal judge had made an error, and allowed California to keep the ban. Again, foie gras producers appealed, this time to the U.S. Supreme Court. But the Supreme Court declined to hear the case, making the previous Ninth Circuit ruling final.
Foie gras producers say that the consumer should be able to make the choice about what they do and don't want to eat. Restaurants, for their part, have tried to find loop-holes. For example, some have given away foie gras for "free" when other expensive dishes were purchased.