Your Grammar Nazi

Ed Kilgore, who knows better:

" ...a magical incantation that had an affect the opposite of that intended by Congress."

Many highly educated people who know better get this wrong, because it's tricky.

Both affect and effect are both verbs and nouns, but they are not interchangeable. They have four different meanings.  Yeah, English sucks.

From Dictionary.com:

Affect

In order to understand the correct situation in which to use the word affect or effect, the first thing one must do is have a clear understanding of what each word means. The word affect means to produce a change in something.

Effect

The word effect has a different meaning. Effect is defined as a result of something or the ability to bring about a result.

Grammar Rules for Affect and Effect

Now that we have the two definitions, how do we know which word to use? Here are a few suggestions to keep in mind:
1. If you are talking about a resrammult, then use the word "effect."

• Example: What effect did the loss have on the team?

2. It is appropriate to use the word "effect" if one of these words is used immediately before the word: into, on, take, the, any, an, or and.

• Example: The prescribed medication had an effect on the patient's symptoms.
• Example: In analyzing a situation, it is important to take the concepts of cause and effect into consideration.

3. If you want to describe something that was caused or brought about, the right word to use is effect.

• Example: The new manager effected some positive changes in the office. (This means that the new manager caused some positive changes to take place in the office.)

4. Affect can be used as a noun to describe facial expression.

• Example: The young man with schizophrenia had a flat affect.
• Example: The woman took the news of her husband's sudden death with little affect.

5. Affect can also be used as a verb. Use it when trying to describe influencing someone or something rather than causing it.

• Example: How does the crime rate affect hiring levels by local police forces?
• Example: The weather conditions will affect the number of people who come to the county fair this year.

So,  Kilgore obviously meant to say

" ...a magical incantation that had an effect the opposite of that intended by Congress."

But he was writing about the stupidity of the Halbig decision and congressional repugs, so he wasn't in a grammatical frame of mind.