They are friends with some big drugs dealers, who visit their house often.Detective Mader decided to follow up on the tip, obtaining further information that an "L. Gates" had purchased an airline ticket leaving from Chicago's O'Hare Airport and arriving in West Palm Beach, Florida.

Working with the DEA, Mader was able to ascertain that Gates had boarded the plane and arrived in West Palm Beach.

The main question that was presented was, "May a judge issue a search warrant on basis of partially corroborated anonymous informant's tip?"

Justice Rehnquist stated: We agree with the Illinois Supreme Court that an informant's "veracity," "reliability" and "basis of knowledge" are all highly relevant in determining the value of his report.

We do not agree, however, that these elements should be understood as entirely separate and independent requirements to be rigidly exacted in every case... [T]hey should be understood simply as closely intertwined issues that may usefully illuminate the common sense, practical question whether there is "probable cause" to believe that contraband or evidence is located in a particular place.This rejected the Aguilar–Spinelli test and put in place a totality-of-the-circumstances standard.

This was put into place because the court recognized that there was more evidence that the Gates family were involved in drug trafficking than just the letter standing alone.

The court also recognized that under the Aguilar–Spinelli two-pronged test, it would be very hard for the "reliability" prong to ever be satisfied from an anonymous tip so it therefore should be abandoned.

The dissenters stated,"By replacing Aguilar and Spinelli with a test that provides no assurance that magistrates, rather than the police, or informants, will make determinations of probable cause; imposes no structure on magistrates' probable-cause inquiries; and invites the possibility that intrusions may be justified on less than reliable information from an honest or credible person, today's decision threatens to obliterate one of the most fundamental distinctions between our form of government, where officers are under the law, and the police-state, where they are the law."

He stated that the exclusion of the evidence would have set the criminals free and it would not have served "any constitutional interest in securing compliance with the important requirements of the Fourth Amendment."

Lance Gates' stay at a motel for one night and immediate return to Chicago suggests that he was not going for a vacation and also implies that he might be involved in something illegal.

The Court, after having heard oral argument, furthermore requested in November 1982 that the parties and amici submit briefs on the broader issue of whether the exclusionary rule should be modified.