When the owner doesn't want to sell, the government would have to try to acquire the land with eminent domain power. (politics.stackexchange.com)
At some point later in the process, they have to be certified by a higher authority to have that eminent domain power. (dailyfreeman.com)
The firm lost its most prominent case to date, however: Kelo v. City of New London, in which it challenged a city's sweeping eminent domain powers before the Supreme Court. (inc.com)