The World Trade Organization’s ruling in a national security dispute between Ukraine and Russia was “seriously flawed,” the Trump administration said during a WTO dispute settlement meeting in Geneva April 26.

The WTO formally adopted its first ruling, on a national security dispute that both affirms the rights of nations to impose trade restrictions on national-security grounds and asserts the WTO’s authority to determine whether a security threat warrants such restrictive measures.

The Trump administration, which previously argued that the...