(adapted from: http://schoolnet.org.za/twt/09/M9_argumentation.pdf)
In his work on logic and argument, The Uses of Argument, Stephen Toulmin indicates three major, necessary parts of an argument, along with three additional, optional parts. The three major parts are the claim, the support, and the warrants.
Claim: This is the disputable assertion for which a speaker argues. The claim may be directly stated or the claim may be implied. You can find the claim by asking the question, "What is the author trying to prove?"
Support: These are the reasons given in support of the claim; they are also known as evidence, proof, data, arguments, or grounds. The support of a claim can come in the form of facts and statistics, expert opinions, examples, explanations, and logical reasoning. You can find the support by asking, "What does the author say to persuade the reader of the claim?"
Warrants: These are the assumptions or presuppositions underlying the argument, explaining why or how the data supports the claim. Warrants are generally accepted beliefs and values, common ways our culture or society views things; because they are so commonplace, warrants are almost always unstated and implied. The author and audience may either share these beliefs, or the author’s warrants may be in conflict with audience’s generally held beliefs and cultural norms and values. Warrants are important because they are the "common ground" of author and audience; shared warrants invite the audience to participate by unconsciously supplying part of the argument. Warrants are also important because they provide the underlying reasons linking the claim and the support. You can infer the warrants by asking, "What’s causing the author to say the things s/he does?" or "Where’s the author coming from?"
Here’s a visual representation and an example:
In this example, the claim that universities should reinstate affirmative action polices is supported by