In the 1970s, Congress passed several laws that mandated economic sanctions against any foreign country that reduced the effectiveness of the International Convention for the Regulation of Whaling. In 1981, Japan exceeded the quotas under ICRW. In 1984, U.S. and Japan later entered into an international executive agreement allowing Japan to continue whaling in the short term until 1988.
Shortly before the executive agreement took effect, several conservation groups filed a mandamus action compelling certification for economic sanctions against Japan. D.D.C. decided, and D.C. Circuit affirmed, that the certification was warranted.
The Supreme Court reversed. The Supreme Court found first that although the matter touched upon politics, it is not a non-justiciable political question. Then the court found that the Congressional acts did not require the executive to give certification whenever there was a violation of the ICRW.
This 5-4 case broke along a strange line. Justices White, Burger, Powell, Stevens and O'Connor formed the majority, while Justices Marshall, Brennan, Blackmun and Rehnquist dissented. But that tends to be the case when we deal with esoteric issues of federalism. You wouldn't think that liberal judicial giants such as Thurgood Marshall, William Brennan and Harry Blackmun to join in with William Rehnquist in restricting the latitude of the executive branch, but such is how it worked in the 1980s.