Eventually Netanyahu backed down and declared a new “red line.”
Yet Israel has not attacked despite Iran stepping over the red line of starting enrichment in Fordow.
Panetta said the U.S. red line was that Iran would not be allowed to cross this Rubicon and go on to develop a nuclear weapon.
They acted as a protective cordon and chanted, "Egyptian women are a red line."
And I think he knows that having said “red line,” he has to enforce it.
The red line answered with a cheer, for their fighting blood was up, and they dashed forward to meet us.
The red line on the floor led to the planet section, which was what he wanted.
They watched silently until the dot had crawled over the circle's red line, heading toward its center.
Chequered in squares of one inch, and a red line at every ninth inch.
It was a very thin gray line along there, back of a thin, red line of clay.
also red-line, "mark in red ink," 1820, from red (adj.1) + line (v.). Specific sense of "deny loans to certain neighborhoods based on ethnicity" is from 1973, on notion of lines drawn on maps. Used earlier in reference to insurance company practices (1961) and in World War II military slang in reference to a red line drawn through a soldier's name for some infraction, thus denying his pay. Related: Redlined; redlining.