Hein v. Freedom From Religion Foundation actually opposed barring taxpayer suits against executive branch
Hein, is a "plurality opinion" decision, i.e., there is no majority opinion. Wikipedia says about plurality-opinion decisions,
In Marks v. United States, 430 U.S. 188 (1977), the Supreme Court explained how the holding of a case should be viewed where there is no majority supporting the rationale of any opinion: “When a fragmented Court decides a case and no single rationale explaining the result enjoys the assent of [the majority], the holding of the Court may be viewed as that position taken by those Members who concurred in the judgments on the narrowest grounds.” Marks, 430 U.S. at 193.
However, the Supreme Court has said that the courts have found it difficult or impossible to apply this "Marks rule" or have disagreed about whether the Marks rule should be applied in specific instances. In Nichols v. United States, 511 U. S. 738, 745-746 (1994), the Supreme Court said,
In Marks v. United States, 430 U.S. 188 (1977), we stated that "[w]hen a fragmented Court decides a case and no single rationale explaining the result enjoys the assent of five Justices, `the holding of the Court may be viewed as that position taken by those Members who concurred in the judgments on the narrowest grounds . . . .' " Id., at 193, quoting Gregg v. Georgia, 428 U.S. 153, 169, n. 15 (1976). This test is more easily stated than applied to the various opinions supporting the result in Baldasar. A number of Courts of Appeals have decided that there is no lowest common denominator or "narrowest grounds" that represents the Court's holding. See, e. g., United States v. Castro Vega, 945 F. 2d 496, 499-500 (CA2 1991); United States v. Eckford, 910 F. 2d 216, 219, n. 8 (CA5 1990); Schindler v. Clerk of Circuit Court, 715 F. 2d 341, 345 (CA7 1983), cert. denied, 465 U.S. 1068 (1984). Another Court of Appeals has concluded that the holding in Baldasar is Justice Blackmun's rationale, Santillanes v. United States Parole Comm'n, 754 F. 2d 887, 889 (CA10 1985); yet another has concluded that the "consensus" of the Baldasar concurrences is roughly that expressed by Justice Marshall's concurring opinion. United States v. Williams, 891 F. 2d 212, 214 (CA9 1989). State courts have similarly divided. [n.10] The Sentencing Guidelines have also reflected uncertainty over Baldasar. [n.11] We think it not useful to pursue the Marks inquiry to the utmost logical possibility when it has so obviously baffled and divided the lower courts which have considered it. This degree of confusion following a splintered decision such as Baldasar is itself a reason for reexamining that decision. Payne v. Tennessee, 501 U. S. ___, ___ (1991) (slip op., at 18-19); Miller v. California, 413 U.S. 15, 24-25 (1973). (emphasis added)
And in Grutter v. Bollinger, 539 U.S. 306, 325 (2003), the Supreme Court said,
In the wake of our fractured decision in Bakke, courts have struggled to discern whether Justice Powell's diversity rationale, set forth in part of the opinion joined by no other Justice, is nonetheless binding precedent under Marks. In that case, we explained that "[w]hen a fragmented Court decides a case and no single rationale explaining the result enjoys the assent of five Justices, the holding of the Court may be viewed as that position taken by those Members who concurred in the judgments on the narrowest grounds." 430 U. S., at 193 (internal quotation marks and citation omitted). As the divergent opinions of the lower courts demonstrate, however, "[t]his test is more easily stated than applied to the various opinions supporting the result in [Bakke]." Nichols v. United States, 511 U. S. 738, 745-746 (1994). Compare, e. g., Johnson v. Board of Regents of Univ. of Ga., 263 F. 3d 1234 (CAll 2001) (Justice Powell's diversity rationale was not the holding of the Court); Hopwood v. Texas, 236 F. 3d 256, 274-275 (CA5 2000) (Hopwood II) (same); Hopwood I, 78 F.3d 932 (CA5 1996) (same), with Smith v. University of Wash. Law School, 233 F. 3d, at 1199 (Justice Powell's opinion, including the diversity rationale, is controlling under Marks).
The Marks rule ought to be repudiated and each plurality-opinion decision should be interpreted on a case-by-case basis. Here is my interpretation of the Hein decision:
(1) There is no distinction between Congressional and executive-branch spending authorizations in regard to taxpayer standing in establishment clause cases. The Hein opinions show that a 6-3 majority of the justices expressly supported this position.
(2) Scalia's recommendation -- joined by only Thomas -- that taxpayer standing in establishment clause cases be completely eliminated -- i.e., a recommendation that Flast v. Cohen be overturned -- was just that, just a recommendation, and should be treated as dictum rather than an opinion of the court.
(3) The 3-justice "judgment of the court" (Alito's opinion) should be re-labeled "dissenting opinion" and the 4-justice "dissenting opinion" (Souter's opinion) should be re-labeled "judgment of the court."
(4) In accordance with the above rulings, the Freedom From Religion Foundation should have been granted standing to sue.
The Wikipedia article about plurality opinions has some errors. The Wikipedia article said,
. . .the plurality opinion did not receive the support of half the justices, but received more support than any other opinion.
In Hein, the opinion called the "judgment of the court" was a three-justice opinion and the opinion called the "dissent" was a four-justice opinion. Some consider Justice Powell's one-man opinion in Bakke to be the opinion of the court.
It is crucial to note that plurality opinions are not binding. They are often treated as majority opinions, because by the time a similar case is considered, a 5th Justice has come around. However, in reality, they are just interesting dicta, showing continued flux and ambivalence on the part of the Court.
Wrong -- plurality opinions are often treated as binding. A plurality opinion in Hein is treated as binding. Also, the above statement is self-contradictory -- majority opinions are binding, so a plurality opinion is binding if it is treated as a majority opinion.
Here is an article about the Marks rule.
Hopefully someday the Supreme Court will throw out the stupid taxpayer-standing idea completely. As I said, there is no fair way to apply this idea because some establishment clause violations are taxpayer-funded while others are not. There are other reasons why the taxpayer-standing idea is bad.