draw a line in the sand(redirected from draw the line in the sand)
draw a line in the sand
Fig. to create or declare an artificial boundary and imply that crossing it will cause trouble. Todd drew a line in the sand by giving his roommate an ultimatum about his sloppiness—he had to start cleaning up after himself or move out.
draw a line in the sandalso draw the line in the sand
to say that a particular idea or activity will not be supported or accepted The president has drawn a line in the sand, which means that if the foreign troops are not removed, they will be attacked.
Etymology: based on the idea of literally making a mark in sand to show someone they cannot move across it