Tow the line. For Corn’s sake, how would you tow a fricking line?
Originally, “...toe the line...”, to stand with one’s toe on the starting or boundary line, therefore to follow the rules, to stay within the defined limits. Also, in old bare-knuckle prize-fighting, after one is knocked down, to stand up and indicate one is ready to go on by standing with one’s toe on a line drawn across the ring, to “come to scratch.”