There is some ambiguity as to the meaning of the term, although you may have enough context to decide:
If I am attempting to connect two or more topics, one could say that I am "trying to draw a clear line (meaning connection, association, or relationship) between them." As in, "as the detective looked at the suspects' photographs tacked to his bulletin board, a clear line began to form in his mind, connecting each of their stories, and weaving a far more believable narrative."
Likewise, if I'm trying to make their differences more stark, one could say that "I have drawn a clear line (or 'drawn clear lines') separating them. As in, "there are some profound differences between the political parties... clear lines can be drawn, separating each and serving to box in their views on each of the key topics."
Finally, it can also mean to create a barrier or a wall. As in "the man stepped smartly forward. Using the toe of his boot, he proceeded to draw a clear line in the sand, slowly and deliberately, as if daring either of his attackers to cross it."