A warrant is a reason that a claim is true.
A claim without a warrant is merely an assertion; it is a statement of opinion without explanation or justification.
If the claim is important because it gets the audience pointed in the right direction, the warrant is important because it helps the audience start moving down the path of the argument. The warrant should immediately follow the claim and should specify, explain, or justify it.
Like claims, warrants should be structured in a very specific way. They should be introduced with language that indicates the speaker is providing a warrant. The most basic way to do this is with a phrase such as “This is true because . . . ” or “This is the case because . . . ” By beginning warrants in this specific way, speakers are verbally prompting themselves to make clear arguments; this is important because debaters are often speaking extemporaneously from notes and may otherwise stray from the structure of their argument.
Many types of warrants are possible for claims. The sample claim, “The first reason to affirm the resolution is because it will stimulate economic growth,” can be advanced with several different warrants.
For example, a warrant may specify how the claim will occur: “It will do this by putting more money into the hands of investors, who pass the money along to businesses and boost production.”
A warrant may also explain why a claim will occur: “This is true because tax cuts lead to an increase in investor confidence.”
Every sentence in an argument should advance the argument in some way, but this is especially important when first presenting an idea. If the argument stalls in the first two sentences, or if the argument grows less clear in the second sentence, then the audience will lose interest.