In the case of Skelly Oil Co. et al. v. Phillips Petroleum Co., the U.S Supreme Court was tasked with determining whether a federal court had jurisdiction over a contract dispute between two oil companies, despite both being incorporated in Delaware and having their principal places of business in Kansas and Oklahoma respectively. The controversy arose from an agreement for Phillips to supply natural gas to Skelly, which later claimed that Phillips failed to deliver the agreed-upon amount leading to significant losses. While initially filed in state court, it was removed by Phillips on grounds of diversity jurisdiction - arguing that because they were citizens of different states (Delaware vs Kansas/Oklahoma), it fell under federal purview. However, the Supreme Court disagreed with this interpretation ruling 5-4 against Philips' claim for diversity jurisdiction as per Section 1332(a)(1) of Title 28 United States Code (USC). They held that corporations are considered citizens only where they have been incorporated or where their principal place of business is located; not merely due to operations or assets within another state's boundaries. This decision clarified corporate citizenship rules regarding diversity jurisdiction thereby limiting instances when cases could be moved from state courts into more favorable federal ones based purely on interstate activities.

In the dissenting opinion for Skelly Oil Co. et al. v. Phillips Petroleum Co., Justice Jackson argued that the majority's interpretation of Section 1331(a) was too narrow and restrictive, limiting federal jurisdiction only to cases where a federal question appears on the face of a well-pleaded complaint. He contended that this approach ignored other important factors such as whether there is an actual controversy between parties over a substantial federal issue or if it involves significant public interest in its resolution by federal courts rather than state courts. Furthermore, he believed that this decision would lead to unnecessary litigation and confusion because plaintiffs could manipulate their complaints to either include or exclude a federal question depending on whether they wanted their case heard in state or federal court.