In Camps Newfound Owatonna, Inc. v. Town of Harrison (1997) 520 U.S. 564, the court found that an exemption from state property tax for property owned by charitable institutions, which excluded from the exemption organizations operated principally for the benefit of nonresidents, violated the commerce clause. (520 U.S. at pp. 572, 576 "As a practical matter, the statute encourages affected entities to limit their out-of-state clientele, and penalizes the principally nonresident customers of businesses catering to a primarily interstate market.".) The court recognized that "the discriminatory burden is imposed on the out-of-state customer indirectly by means of a tax on the entity transacting business with the non-Maine customer," but "this distinction makes no analytic difference." (Id. at p. 580 "'imposition of a differential burden on any part of the stream of commerce--from wholesaler to retailer to consumer--is invalid, because a burden placed at any point will result in a disadvantage to the out-of-state producer'".) And, "the statute provides a strong incentive for affected entities not to do business with nonresidents if they are able to so avoid the discriminatory tax. In this way, the statute is similar to the North Carolina 'intangibles tax' that we struck down in Fulton ... ." (Id. at p. 578.) As the Camps Newfound court further stated: "That the tax discrimination comes in the form of a deprivation of a generally available tax benefit, rather than a specific penalty on the activity itself, is of no moment" (Camps Newfound, supra, 520 U.S. at pp. 578-579), and "there is no ' "de minimis" defense to a charge of discriminatory taxation under the Commerce Clause' " (id. at p. 581, fn. 15). In rejecting the state's contention that tax exemptions for not-for-profit entities should be treated differently under the commerce clause, the court observed: "If we view the issue solely from the State's perspective, it is equally reasonable to use discriminatory tax exemptions as a means of encouraging the growth of local trade. But as our cases clearly hold, such exemptions are impermissible." (520 U.S. at p. 588 "Protectionism ... is forbidden under the dormant Commerce Clause.".)