Verb
(intransitive) To lay down a challenge; to provide a test of commitment (often one which carries a high risk) to a cause.
To create a real or artificial boundary or distinction between (two places, people or things).
To indicate the threshold or level above which something will become unacceptable or will provoke a response; to create a boundary and imply or declare that its crossing will provoke a (negative) response.
Source: en.wiktionary.orgJudy Miller is the most innocent person in this case. I really thought that was outrageous that she was jailed and we needed as journalists to draw a line in the sand in a strong but thoughtful way. Tom Brokaw