United States environmental law is a “legal system of statutes, regulations, guidelines, requirements, policies, and case-specific judicial and administrative interpretations” that is used to minimize or prevent behaviors that may negatively affect the environment and public health, (pp.1-4).  One major piece of federal legislation, the Endangered Species Act (ESA), passed in 1973, broadly protects threatened or endangered plants and animals and their critical habitats, (p.715).  Once a species is listed as endangered, the ESA is granted authority to regulate all public and private behavior that may impact listed species, (p.715).  The ESA protects listed species by forbidding actions that may “harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect” species including the modification or degradation of its critical habitat, (p.716). 
In recent political and legal debate, the ESA has come under controversy regarding whether or not the law is constitutional and whether or not the federal government has the authority to intervene in the property rights of individuals under this law. Under the X Amendment, the federal government must not encroach on state power unless granted authority by the U.S. Constitution.  At the time of the act’s passing, Congress argued it had authority to enforce species protection laws on the federal level and override state’s rights because of the U.S. Constitution’s Commerce Clause, which grants Congress the authority to regulate interstate commerce. 
The argument against the constitutionality of the ESA is whether or not species only found in one state should be considered “interstate commerce” when the species does not cross state boundaries.  In a recent case that may be seen by the U.S. Supreme Court, Texas rancher John Yearwood is in a legal battle to determine if his private property can be regulated under ESA law given the listed endangered species in question, the Bone Cave Harvestman spider, was found living on his land.  Yearwood’s attorney argues the spider is not a commercially viable species and that since it is located only in Texas, does not warrant interstate regulation. 
In my opinion, while I agree with the purpose of the EPA that endangered species and their habitats should be protected from extinction, the use of the Commerce Clause to justify the EPA is unconstitutional as it is hard to determine how endangered wildlife such as spiders, that have no market participation, can be considered “commerce.” If wildlife is found to affect commerce and therefore (by some legal alchemy I do not know) implicated in the clause, then in Yearwood’s case, I would still argue the law is unconstitutional because the listed spider should not be held under “interstate” regulations if 1) it only resides within one state, and 2) there is no substantial evidence the listed spider species’ survival would negatively affect ecosystems beyond state boundaries (the argument all ecosystems are ‘interconnected’  is an anecdotal observation, that while may be true in general, does not evidently demonstrate how one species of spider located in Texas, which is limited in number, will directly affect wildlife in New Mexico, Oklahoma, Arkansas, or Louisiana).
I agree it makes governing sense for the protection of endangered species and their habitats to be a federal responsibility, but the U.S. Constitution was a flawed document that did not foresee, for example, environmental concerns, and therefore such regulation not specified in the U.S. Constitution (like it or not) must be yielded to the states. I agree the Supreme Court’s 1995 ruling that government “may not convert congressional Commerce Clause authority to a general police power of the sort held only by the states” applies in this case.  It appears the Commerce Clause has been used here, albeit in good faith, to unconstitutionally expand the powers of the federal government (and force those pesky states to uphold better standards). It would have made more sense to have enacted an Amendment to the Constitution to grant federal authority over endangered species rather than classify unrelated policy areas as “commerce” or consider two counties in Texas as “interstate” in order to justify unconstitutional overuse of federal power.
 Sullivan, Thomas F. P., Environmental Law Handbook, 22nd Ed. Bernan Press, 2014.
 Cornell Law School, “Commerce Clause,” Wex Legal Dictionary. URL: www.law.cornell.edu/wex/commerce_clause
 Biber, Eric. “The ESA and the Commerce Clause,” Legal Planet Insight & Analysis: Environmental Law and Policy. URL: www.legal-planet.org/2014/11/18/the-esa-and-the-commerce-clause/
 Kerkman, Maggie and Casey Stegall. “Texas Rancher Caught in Regulatory Web After Rare Spider Found on Land,” Fox News, 02 March 2017. URL: www.foxnews.com/politics/2017/03/02/texas-rancher-caught-in-regulatory-web-after-rare-spider-found-on-land.html
 Will, George. “Federal Power Spins Its Ever-Growing Web,” 20 May, 2017. National Review. URL: www.nationalreview.com/article/447813/bone-cave-harvestman-spider-case-tests-commerce-clause-jurisprudence