A company accused of having a smelly plant said it would “continue its efforts to mitigate against any odors.” A financial columnist wrote that “Diversification Doesn’t Totally Protect You from Every Risk; It May Mitigate the Impact of Those Risks.”
A financial report said that the “constant fluctuation in bitcoin’s price seemed to militate against its usefulness as a medium of exchange.” A column on a pro-Palestinian student group said that it “militates to ostracize fellow students who travel to Israel.”
Yes, it’s time for another episode of “similar but different.”
“Mitigate” means to reduce the impact of something, as in making a plant less smelly. “Militate” means to add weight or impact to something, as in adding reasons not to use bitcoin. They are not exactly antonyms, but they have opposite effects: one eases, one increases.
The two words are unrelated etymologically. “Mitigate” comes from words for “soften, alleviate, moderate, assuage,” etc. and dates to the late 15th century. The Oxford English Dictionary says its earliest usage is the most common one today: “To alleviate or give relief from (an illness or symptom, pain, suffering, sorrow, etc.); to lessen the trouble caused by (an evil or difficulty).”
“Militate” is newer, appearing at the end of the 16th century, the OED says. Its first usage is close to the one we see today: “Of a person, institution, etc.: to contend in the manner of a soldier; to exert power or influence; to campaign; to strive.”
As you might expect, “militate” has the same root as “military,” and it carries the same harsh connotations: If you are seeking to “militate” against something, you are not just putting a thumb on the scale. You are throwing your whole body and as many weapons as you can on the scale to get your way. And you need to say which direction you want things to go: You can “militate against” something, or “militate for” something. But “mitigating” is only lessening something, never increasing.
That has led to confusion of another kind: whether either needs a preposition.
Garner’s Modern English Usage notes that “Today, mitigate is almost invariably transitive,” and using it with “against” is nonstandard. “Militate,” however, is generally an intransitive verb, and so needs a preposition to indicate the direction the militation is heading. But beware: Garner’s says that “militate toward” is unidiomatic.
It’s a common shibboleth that “mitigate” and “militate” are confused a lot. By themselves, they aren’t, but the “against” apparently throws people off. Merriam-Webster includes usage notes at both “mitigate ” and “militate”; American Heritage includes a note with “mitigate.” Garner’s says using “mitigate against” when “militate against” was meant is an error that “emerged about 1900 and spread precipitously from 1950,” and is “surprisingly common.” A search of Nexis turns up about 150 instances of “mitigate against” in the past month, many in congressional transcripts or legal proceedings, where “militate against” appears more frequently than in ordinary writing. Garner’s says that using “mitigate against” instead of “militate against” is at Stage 3 of the five-stage Language-Change Index, widespread but still frowned upon.
The New York Times Manual of Style and Usage has an entry covering both of those situations:
Militate against something means exert weight or effect against it: High taxes militate against relocating the plant. Mitigate, which means ease or soften, is never the word to use with against: Tax reductions mitigated the financial pressure.
The Chicago Manual of Style simply notes that “militate” takes “against,” but “mitigate” stands alone. The Associated Press Stylebook says nothing.
Neither “mitigate” nor “militate” is a common word today, though “mitigate” is in the top 10 percent of popular words on Merriam-Webster.com. (“Militate” is in the bottom 50 percent.) This Google Ngram of words appearing in books since the 1800s shows how the usage of both steadily declined in the 20th century, until about 1980, when the fortunes of “mitigate” began to rise.
But because the ngram doesn’t differentiate between “mitigate against” and just plain “mitigate,” there might be mitigating circumstances to explain the apparent increase.