what existing legislation are there that protects businesses from the government?

1. The Fifth Amendment of the United States Constitution protects businesses (and individuals) from government action that would deprive them of "life, liberty, or property, without due process of law."

2. The Fourth Amendment of the U.S. Constitution also protects businesses from unreasonable searches and seizures by the government.
3. The Sherman Antitrust Act of 1890 protects businesses from anti-competitive practices by other businesses or the government.
4. The Foreign Corrupt Practices Act of 1977 protects businesses from bribery and corrupt practices in their dealings with foreign governments.
5. The Administrative Procedures Act of 1946 requires government agencies to follow certain procedures when regulating businesses, providing businesses with a level of due process in agency actions.
6. The Small Business Regulatory Enforcement Fairness Act of 1996 provides protections for small businesses from excessive regulatory enforcement by the government.