Everyone has language pet peeves: those little things people say that aren’t quite right, and that we can’t help but correct. For reader Mark Freeman, it’s the phrase “step foot in,” as in “I wouldn’t step foot in (or into) his messy apartment.” He says: “This is a misuse for ‘set foot in.’ ‘Set’ is transitive, ‘step’ not, which is why we don’t say ‘I stepped my foot onto his scrawny neck.’”
The “proper” use of the phrase is indeed “set foot in.” “Set” in this case is a transitive verb, meaning it needs an object to act upon—the foot. (While Mr. Freeman is right that “step” is not transitive here, it can be. But that would be another step.) You’re not just “stepping in”; you are deliberately contemplating the consequences of going into your friend’s messy apartment.
Here’s another way to look at it: When you walk, you step. Each time you step, you set your foot down. When you walk into a place, you step into it; you set foot into it. “Step” is pure action; “set” implies deliberation. Makes perfect logical sense.
Logic, however, means nothing to English speakers. We like nothing more than to mangle, er, modify, time-honored phrases. Thus “the proof of the pudding is in the eating” gets shortened to “the proof is in the pudding,” which makes no sense unless it’s a brandy pudding, and it’s eighty proof.
“Set foot in” is an idiom, meaning it’s the way people usually use a phrase. Yet “step foot in” or its close variants have appeared countless times in news reports in the last year. And had Nexis existed in the 1500s, it would’ve picked up on more than a few uses then, as well. (The Oxford English Dictionary got there first.)
Most of the time, however, the phrase appears in quotations, indicating that it is a mostly verbal tic. Despite some claims that this is a purely American phenomenon, it appears as frequently in British/Australian/Canadian publications, if not more so. It doesn’t show up in usage guides, though, blunting the criticism of those who claim it is patently wrong.
Nonetheless, careful writers won’t step—er, set—er, well, they won’t go there.