In Toomer v. Witsell, 334 U.S. 385, the Supreme Court set forth the standard of review of a privileges and immunities clause claim as follows: "Like many other constitutional provisions, the privileges and immunities clause is not an absolute. It does bar discrimination against citizens of other States where there is no substantial reason for the discrimination beyond the mere fact that they are citizens of other States. But it does not preclude disparity of treatment in the many situations where there are perfectly valid independent reasons for it. Thus the inquiry in each case must be concerned with whether such reasons do exist and whether the degree of discrimination bears a close relation to them. The inquiry must also, of course, be conducted with due regard for the principle that the States should have considerable leeway in analyzing local evils and in prescribing appropriate cures." (Ibid.) In the face of a proper substantial reason, there may be constitutionally valid discrimination under the privileges and immunities clause. Toomer further defined the justification that must be present in order for a nonresident's privileges and immunities clause claim to be rejected as follows: "The purpose of that clause . . . is to outlaw classifications based on the fact of non-citizenship unless there is something to indicate that non-citizens constitute a peculiar source of the evil at which the statute is aimed." (Toomer v. Witsell, supra, 334 U.S. at p. 398 68 S. Ct. at p. 1163)