The second of the holiday display in question was an 18-foot (5.5 m) public Hanukkah menorah, which was placed just outside the City-County Building next to the city's 45-foot (14 m) decorated Christmas tree and a sign saluting liberty.

In a complex and fragmented decision, the majority held that the County of Allegheny violated the Establishment Clause by displaying a crèche in the county courthouse, because the "principal or primary effect" of the display was to advance religion within the meaning of Lemon v. Kurtzman (1971), when viewed in its overall context.

Its combined display with a Christmas tree and a sign saluting liberty did not impermissibly endorse both the Christian and Jewish faiths, but simply recognized that both Christmas and Hanukkah are part of the same winter-holiday season, which, the Court found, had attained a secular status in U.S. society.

Since 1981, the Holy Name Society of Pittsburgh had placed a crèche on the grand staircase of the Allegheny County Courthouse.

However, Brennan disagreed with Blackmun and O'Connor's respective opinions by stating that the menorah and Christmas tree are also violations of the Establishment Clause.

[4] He believed that the menorah display, together with the Christmas tree, signified a double violation of the establishment clause.

"[5] By placing the menorah with the Christmas tree, she believed that the city is representing the pluralism of the freedom of religion.

In III-B, Justice Blackmun sets the issue of the case as deciding if the crèche and menorah have "the total effect of endorsing or disapproving religious beliefs."

Justices Blackmun and Brennan also argue that Hanukkah's social prominence in America may be due to the proximity to Christmas.

"[5] Justice Blackmun found that the crèche endorsed a "patently Christian message," and permanently enjoined its display in the context presented.

[1] In his dissenting opinion, Justice Kennedy believed that the crèche does not fail the second prong of the Lemon test, and its display is therefore constitutional.