Congress had passed a statute allowing U.S. citizens born in Jerusalem to have 'Israel' listed as their place of birth on their passports — contradicting the executive branch's longstanding refusal to recognize any nation's sovereignty over Jerusalem. Justice Kennedy's opinion held the statute unconstitutional. Drawing on the Reception Clause of Article II, historical practice, and functional necessity ('the Nation must speak with one voice' on recognition), the Court concluded that recognition is an exclusive presidential power that Congress cannot override even indirectly through passport regulation. Zivotofsky is the first modern case squarely striking down an act of Congress on separation-of-powers grounds in the foreign-affairs arena, and it remains the leading authority on the recognition power.