Eminent domain stinks and it’s stunk worse since the Kelo decision.
The U.S. government has used eminent domain to acquire land for existing sections of the border fence, and legal precedent is on Trump’s side. In 2005, the Supreme Court ruled, in Kelo v. The City of New London, that local governments may force property owners to sell out and make way for private economic development when officials decide it would benefit the public.*
Still, attempts to acquire land would certainly face challenges in court. Historically, wall-related land cases have taken years to resolve, with costly settlements often resulting. An Associated Press review of border-related eminent domain cases in 2012 found that the U.S. government spent approximately $15 million to acquire 300 properties along the border in Texas.
*In other words, if the rich guys can pay more taxes to the city than you can the rich guys likely get to bulldoze your house for new condos.