What is the origin of the idiom "Mexican standoff" and when to use it?

The idiom "Mexican standoff" is believed to have originated in the American West in the late 19th century, where it was used to describe a confrontation between cowboys, outlaws, or lawmen, who were all armed and facing off against each other. In modern usage, the term "Mexican standoff" is often used to describe a tense situation where two or more parties are at a standoff and neither side is willing to back down or make a move.