Antonyms for the phrase "lays foundation for" can include "tears down," "destroys," "ruins," "undermines," and "abolishes." These words imply a negative or destructive action that opposes the idea of establishing or building a foundation, which is what laying a foundation for something implies. For example, tearing down a building would be the opposite of laying a foundation for one. Similarly, destroying an idea or a plan would be the opposite of laying a foundation for it. Therefore, these antonyms can be useful when discussing situations where the establishment of a strong foundation is not desirable or where actions were taken to prevent it.