Courts sometimes invoke a doctrine called Judicial Estoppel. Essentially, it means you can’t take two positions or make two arguments (often in the same case) that are inconsistent with each other. A classic example is a border argument between Maine and New Hampshire, in which New Hampshire, having previously agreed to a certain border to settle a lawsuit [New Hampshire v. Maine, 426 US 363 (1977)], tried to claim some land was in New Hampshire in a different lawsuit against Maine [New Hampshire v. Maine, 532 U.S. 742 (2001)]. The US Supreme Court argued that New Hampshire could not, after agreeing to the borderline in the 1977 case, now argue that the border was different.
In a recent Wisconsin case, Gerhartz v. Town of Lomira, Eugene and Catherine Gerhartz won and lost. The Town had permitted one of Gerhartz’ neighbors to place a pipe (for pumping manure) and manhole in a Town right of way on the Gerhartz’ property. Gerhartz sued the Town for inverse condemnation, a “taking.” Gerhartz was successful in arguing that the Town had taken Gerhartz’ property without just compensation, and was awarded compensation.
Gerhartz also sued the neighbors, Jeff and Brenda Elsinger, for trespass. The trespass claim was based on the fact that the Town had no authority to allow the Elsingers to use the town right of way for private purposes (pumping manure).
The court held that the Gerhartz could not argue both that the taking was valid and receive compensation for the taking, and also argue that the taking was invalid, and receive compensation for trespass.