While the question of public use gets most of the ink, there's another showing that governments must make before they take private property. State actors seeking to use their eminent domain power must prove that the target property is "necessary" to effect the stated public use.
Otherwise, of course, the government could find any valid public use and, in theory, condemn every parcel within their jurisdiction by claiming it's part of the project.
That appears to be the thinking of Broward County, Florida. Officials there sought to take property to build a drug treatment center. Unfortunately, they decided to take considerably more property than anybody, including the city involved, thinks is necessary for the project.
Some of this extra property is owned by the Christian Romany Church. PLF filed an amicus brief supporting the church, arguing broadly that government claims of necessity should be reviewed with the same strict scrutiny that courts use when assessing other issues of fundamental rights, and specifically that the County's actions can't survive that scrutiny.
The church lost at trial, and appealed the decision. Oral argument was this week. A PLF press release on the case is available here.