Illinois v. Gates 462 U.S. 213, 103 S. Ct. 2317, 76 L. Ed.2d 527 (1983)
The police received an
anonymous letter saying that the Gates' were traveling between Illinois
and Florida transporting drugs.
The police found out that Mr.
Gates had indeed bought a plane ticket to Florida. They followed him and
saw him meet with someone and then drive back to Illinois.
Gates' behavior was mostly
similar to what was described in the letter.
Based on the letter and their
surveillance, the police swore out an affidavit for a search warrant. The
warrant was granted, the police searched Gates' car and found a large
quantity of drugs. He was arrested.
The Trial Court found that
there was no probable cause and so
the warrant was insufficient and therefore the drug evidence was
inadmissible. The prosecutor appealed.
Gates argued that the police
did not have sufficient probable cause for the warrant, and therefore the search was a violation of the
The Appellate Court affirmed.
The prosecutor appealed.
The Appellate Court looked
to Spinelli v. United States (393
U.S. 410 (1969)), which had a two-pronged test that basically said that a
warrant can't be based on an informer's information unless the affidavit
for the warrant also explained why the informer was reliable, and what
the underlying circumstances of the informer's information were.
Known as the Aguilar-Spinelli
The letter provided nothing
that would let a magistrate conclude that the author is honest or that
his information is reliable. It also gave no indication of how the
author came upon the information.
The Illinois Supreme Court
affirmed. The prosecutor appealed.
The US Supreme Court reversed
and found that there was sufficient probable cause.
The US Supreme Court
reversed their decision is Spinelli,
finding that the courts should look at the totality of the
circumstances when deciding if there is probable cause.
"The task of the
magistrate is simply to make a practical common-sense decision whether,
given all the circumstances set forth in the affidavit before him,
including the 'veracity' and 'basis of knowledge' of persons supplying
hearsay information, there is a fair probability that contraband or
evidence of a crime will be found in a particular places."
The Court found that while
the veracity and basis of knowledge of an anonymous tipster cannot be
measured, when corroborated by the actions of the Gates, it satisfies the
requirement to establish probable cause.
"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. They 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."
The Court noted that if the
only thing that the police had was the anonymous letter, that alone would
not be sufficient to establish probable cause. However, the letter combined with their
other police work was enough.
Basically, in this case, the
Court was saying that the requirement for probable cause is not as high as for admissibility at a formal
trial. It is enough for the magistrate to decide that there is a fair
probability that the informer is telling the truth. In this case, the
corroboration of much of the letter's contents by the police investigation
should be sufficient to establish that the letter writer was reliable and
had a good basis for their information.
At the end of the day, this
ruling wasn't much different than Spinelli. It just makes the analysis less formalistic and somewhat
combines the two prongs.
The main differences
between the Aguillar-Spinelli Doctrine and the Totality of the Circumstances Test are that under the Totality of the
Circumstances Test, a deficiency in
one prong can be made up for by a strong showing in the other prong, and
there is no bright line rule about how much is required, it is an
If one prong is completely
missing, then there is not enough to give probable cause.