In good news for property rights, the Supreme Court granted cert this term to hear a case about a kind of abuse that has been festering for nearly 100 years.

“Rails to Trails” is a program that hands over huge swaths of private land to the federal government. The government’s access is based on old contracts, but landowners never actually got paid for a permanent taking.

It all started with the 19th century railroad craze. In the 1800s, the federal government used sweeping incentives to encourage companies and individuals to invest in railroads. First, the government deeded huge tracts of public land to railroads, then it encouraged the railroads to negotiate access to private land in order to lay tracks.

These negotiations were quick and effective, and they turned on the idea that railroads brought wealth and prosperity. Railroads quickly acquired access to private land across the country.

However, the access landowners granted railroads wasn’t unconditional and it wasn’t intended to be permanent. Landowners typically negotiated easements, or partial access to someone else’s land. These easements were typically written so that in the event the railroads abandoned the right of way, access rights would revert back to the landowners’ control. Railroad contracts clearly reflected landowners’ expectation that they would either flourish or get their land back, granting easements for as low as $1.

Landowners first glimpsed the fact that railroads had gotten too greedy in 1920, when Congress passed a law allowing railroad easements to be used for non-railroad purposes. In 1976, the Railroad Revitalization and Regulatory Reform Act was passed with a little-noticed section setting up a grant program for Rails-to-Trails. In 1983, the Trails Act set the stage for morphing railway passages into public parks. Then in 1988, Congress passed the National Trails System Improvement Act, a “railbanking” statute to preserve the government’s easements even where rail passages had been abandoned.

Railbanking –which was already the subject of a 1990 Supreme Court challenge in Preseault v. United States – torpedoed the understanding that provided the basis for most railroad easement contracts. Had landowners realized these easements were permanent, they would have negotiated dramatically different contracts. Landowners also would have negotiated differently had they realized the purpose of the easements would change. Having a train pass through your backyard is a dramatically different experience than having people peering in your windows, as anyone who has walked Manhattan’s High Line (a Rails to Trails park) knows.

Even as litigation continues, state and federal government press forward with this program. Just this month, California passed legislation that provides “unprecedented” funding to a Trails program. Supporters of California’s new law credit it with “streamlining the process” and “reduc(ing) administrative inefficiencies.” Which is to say, it looks to cut out litigation with private landowners.

Public parks and trails sound great. But building public land at private individuals’ expense makes little sense and violates basic principles of property law. The U.S. Constitution requires that when government takes private land, it must pay just compensation. The government is trying to get around that requirement here.

The case before the Court this term is Brandt v. United States. The Brandt plaintiff is a family that purchased land subject to an easement that had been abandoned. State property law dictates that the Brandts own the land underlying the easement, and so constitutionally, the government must pay just compensation if it intends to maintain control. One party to a contract should never be allowed to change the contract’s terms unilaterally, and common law property principles always apply.

Instead, the United States filed for title in state court, relying on obscure precedent that scraps common law property principles entirely when it comes to railroad easements. This is a dangerous attempt to circumvent the Constitution, and the court should stop it in its tracks.