The politician's syllogism, also known as the politician's logic or the politician's fallacy, is a logical fallacy of the form:

1. We must do something
2. This is something
3. Therefore, we must do this.

The politician's fallacy was identified in a 1988 episode of the BBC

BBC

The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...

 television political sitcom Yes, Prime Minister titled "Power to the People

Power to the People (Yes, Prime Minister)

"Power to the People" is the thirteenth episode of the BBC comedy series Yes, Prime Minister and was first broadcast 7 January 1988.- Plot :Not for the first time, Jim Hacker is experiencing problems with local government...

", and has taken added life on the internet. The syllogism (invented by fictional British civil servants) has been quoted in the (real) British Parliament.

In Yes, Prime Minister, the term is discussed between two high-ranking civil servants who are concerned that the prime minister wants to implement a scheme to reform local government

Local government

Local government refers collectively to administrative authorities over areas that are smaller than a state.The term is used to contrast with offices at nation-state level, which are referred to as the central government, national government, or federal government...

 due to political opposition there. In this issue, as with many other issues humorously explored by the show, the civil servants believe that doing anything is worse than doing nothing because actions tend to undermine the dominance of the civil service. They identify the politician's logic as a fallacious categorical syllogism:

1. All cats have four legs
2. My dog has four legs
3. Therefore, my dog is a cat.

This invalid

Validity

In logic, argument is valid if and only if its conclusion is entailed by its premises, a formula is valid if and only if it is true under every interpretation, and an argument form is valid if and only if every argument of that logical form is valid....

 form of argument, labeled AAA-2 among syllogisms, commits the fallacy of the undistributed middle

Fallacy of the undistributed middle

The fallacy of the undistributed middle is a logical fallacy, and more specifically a formal fallacy, that is committed when the middle term in a categorical syllogism is not distributed in the major premise...

: it says nothing about all things having four legs (the middle term

Middle term

The middle term must distributed in at least one premises but not in the conclusion of a categorical syllogism. The major term and the minor terms, also called the end terms, do appear in the conclusion.Example:...

) and thus the conclusion cannot logically follow from the premises (even if the premises are sound). The politician's syllogism similarly says nothing about all known "somethings" that could be done. As is common with fallacious undistributed middle arguments, it can also be seen as the fallacy of affirming the consequent

Affirming the consequent

Affirming the consequent, sometimes called converse error, is a formal fallacy, committed by reasoning in the form:#If P, then Q.#Q.#Therefore, P....

 when restated as an equivalent hypothetical syllogism

Hypothetical syllogism

In logic, a hypothetical syllogism has two uses. In propositional logic it expresses one of the rules of inference, while in the history of logic, it is a short-hand for the theory of consequence.-Propositional logic:...

:

1. To improve things, things must change
2. We are changing things
3. Therefore, we are improving things.

The politician's syllogism can also be interpreted as committing the informal fallacy

Informal fallacy

An informal fallacy is an argument whose stated premises fail to support their proposed conclusion. The deviation in an informal fallacy often stems from a flaw in the path of reasoning that links the premises to the conclusion...

 of equivocation

Equivocation

Equivocation is classified as both a formal and informal logical fallacy. It is the misleading use of a term with more than one meaning or sense...

, which is using one word ("something") in two different senses.