(I feel like it might be a bit unnecessary to explain this, but just in case it isn't really clear what I'm referring to, "Pre-constitutional" is referring to the period between the U.S. gaining its independence from Britain and the signing of the U.S. constitution in 1787. I have no idea if people actually call it that).
In a high school government class, I had to watch a video about the many struggles the United States faced during its time under the Articles of Confederation. One of these struggles was that two states were on the verge of declaring war on each other.
I don't recall what the two states were, and any attempts at trying to rediscover this were fruitless. Was it a thing that actually happened?
You may be thinking of the "Pennamite-Yankee War," a conflict over ownership of a tract of land in Pennsylvania claimed by a group of settlers from Connecticut. Tensions led to partisan warfare during the Revolution and weren't fully resolved until 1799.
You may also be thinking of simmering tensions between the state of New York and the independent Republic of Vermont; Ethan Allen's Green Mountain Boys started as an irregular militia to defend not against Britain, but against New York.