Draw A Line In The Sand Meaning

(idiomatic) 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.

Example: 1998, Jerry B. Jenkins; Tim F. LaHaye, Through the flames:
  "Well," Judd said, "what's the deal. You in or out?" "I have to decide right now?" "We have a meeting with Bruce tonight and church tomorrow morning. You go with us tonight and you promise to go tomorrow, or you move out this afternoon." "The man's drawing a line in the sand for you," Lionel said. "Lionel!" Vicki scolded. "I'm just sayin', the line has been drawn. You crossing the line, Ryan? Or are you with us?"
2007, Daniel Pyne, Glenn Gers (scriptwriters), Fracture,
  WILLY: It doesn't have to stick: we just need to get a court order for now - to keep Crawford from pulling the plug! With all the brain-power here, I'm sure somebody can come up with a pretext or call in a favor. Then we can tie this up in court while we arrange a state-appointed conservatorship - so we can protect her while we fight him on -
  NIKKI: What's the point, Willy?
  WILLY: The point?! [Willy stares.] Because she's drawn a line in the sand. One he already crossed, without truly understanding... and now he's standing out there alone.
2008 March 21, Diane Sawyer, “Prostitution in America: Working Girls Speak”, 20/20:
  And Jesus draws a line in the sand and says,' He that is without sin among you, let him cast the first stone."
2010, Robyn Carr, Angel's peak:
  But when it came to marriage and children, she was in, and he, at twenty-eight, was out. She had said something like, "It's time to take this relationship to the next level or end it completely." You don't want to be drawing a line in the sand in front of a young fighter pilot.
1999, John D. Caputo, Michael J. Scanlon, God, the Gift, and Postmodernism, page 133,
  At some point you ask, "Where do we draw a line in the sand between deconstruction as desertification of God and as desertion of God?" There is no line.
2003, Doug Geiger, Mindful Forgiveness: Experiencing the Love Factor, page 42,
  Could it be, that way back, early in this relationship, consciously in my mind, I chose to set a boundary or to draw a line in the sand between this person and myself? This line meant that I would not allow the person to come any closer to me, or my seeming secrets, than that line in my mind.
2004, Sam McKinney, Sailing with Vancouver: A modern sea dog, antique charts and a voyage through time, page 75,
  Puget drew a line in the sand to separate the two parties, which the Natives did not cross though they showed a "distrustful Behaviour."
2008, Niels Peter Lemche, The Old Testament between Theology and History: A Critical Survey, page 306,
  We might think that Albertz—and that is probably also his opinion—has taken up again Gabler's project of 1787 by drawing a line in the sand between historical and dogmatic studies.
2009, Piet Eeckhout, Takis Tridimas, Yearbook of European Law 2009, Volume 28, page 103,
  There is no shortage of examples in which EC competition law and European social law have been at loggerheads while trying to draw a line in the sand separating their respective territories.
2009, Brett Edward Whalen, Dominion of God: Christendom and Apocalypse in the Middle Ages, page 95,
  The fact remains, however, that Honorius's glorification of the Synagogue demonstrates how reformist apocalypticism — even as it drew a line in the sand between the elect and the forces of evil — opened the door to a future transformation that could change the very nature of the elect.
2010, John Portmann, Catholic Culture in the USA: In and Out of Church, page 8,
  One of the advantages of Paglia's phrasing is the way in which it avoids drawing a line in the sand between “good” Catholics and “bad” Catholics.
2003 March 5, Robert Byrd, speech, North Korea: The Rising Peril,
  Even so, the current crisis might well have been defused weeks ago, before the two leaders started exchanging threats of war, had the United States agreed to talk directly to North Korea, as our allies in the region have been pleading with us to do. Instead, the Administration drew a line in the sand, insisting that the United States would not be blackmailed into one-on-one talks with North Korea.
2007, Steve Bickerstaff, Lines in the Sand: Congressional Redistricting in Texas and the Downfall of Tom DeLay, page 185,
  Finally, just as passage of redistricting had been made a litmus test for Republicans, defeating its passage now became a litmus test for Democrats. The Democrats drew a line in the sand.
2008, James Boyle, The Public Domain: Enclosing the Commons of the Mind, Yale University Press, 2008 Gutenberg eBook edition,
  The law has not been entirely one-sided, however. The Sony case drew a line in the sand which promised to halt the inevitable drift toward greater and greater control over communications technology by content owners.