[2] This case arose out of a dispute between two labor unions over the representation of coal miners in Marion County, Tennessee.

UMW field representative George Gilbert was away on business in Middlesboro, Kentucky at the time of the incident, and learned of the violence while he was away.

Here, Brennan established the test for pendent jurisdiction known as the "common nucleus of operative fact": the claims must derive from the same situation, such that a plaintiff would ordinarily expect to try them all in one judicial proceeding.

Brennan concluded that even though the jury ruled against plaintiff on his federal claim, the preemption issue created a particularly good reason for exercising pendent jurisdiction in this case.

Brennan also held that the district court improperly instructed the jury on the conspiracy count, because the damages plaintiff was claiming must be proximately caused by violence or threats thereof, and that plaintiff had not shown "clear proof" that the UMW's management had endorsed violence as a means of settling the dispute (as required under the Norris-LaGuardia Act).

Justice Harlan wrote a brief concurrence, in which he agreed with Brennan's discussion of pendent jurisdiction, but disagreed with his interpretation of the standard of proof required for a claim under the Norris-LaGuardia Act.