In Timbs v. Indiana, the Supreme Court has ruled that States are subject to the Eighth Amendment's excessive fines clause.
Civil-asset forfeiture is a legal process by which law enforcement agencies can seize any property, money, bank funds, you-name-it, by saying the items seized were involved in a criminal activity. They don't have to prove they were or that the person committed any criminal activity. The charge itself is sufficient to allow seizure and the defendant has to prove his innocence.
Here's David French at National Review describing the case:
At issue was the important question of whether the Eighth Amendment’s excessive fines clause applied to the states and whether the excessive fines clause applied to a practice called in rem civil-asset forfeiture. Under this practice, law-enforcement officials often engage in two separate punitive legal processes against criminal defendants. The first is the criminal prosecution itself, which can impose prison sentences and fines according to statutorily defined punishments. The second is often a civil action against the criminal defendant’s property. Yes, the government will file suit against trucks, cars, jewelry, boats, and cash — leading to absurd case captions like, say, Texas v. One Gold Crucifix — claiming that the property was used for criminal purposes and then seize that property under a lower, civil, burden of proof.Law enforcement agencies get to keep the proceeds, so there is a big incentive to finger anything they can for civil-asset forfeiture. French points out that "in 2014, for example, the state took more money from citizens than burglars took from crime victims."
Unfortunately, this is just the first step, as the Supreme Court has left the job of determining what is "excessive" in asset-forfeiture. But, it's a good first step.
What needs to be added beyond determining what is "excessive" is that the person whose property is being seized has to be actually convicted of a crime. Icing on the cake would be that law enforcement or government agencies could not profit by the seizure, but I'm not holding my breath on that one.