cross the Rubicon

Cultural  

1. To make an irrevocable decision; it comes from the name of the river Julius Caesar crossed with his army, thereby starting a civil war in Rome. (See Rubicon.)

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cross the Rubicon Idioms  

1. Irrevocably commit to a course of action, make a fateful and final decision. For example, Once he submitted his resignation, he had crossed the Rubicon. This phrase alludes to Julius Caesar's crossing the Rubicon River (between Italy and Gaul) in 49 b.c., thereby starting a war against Pompey and the Roman Senate. Recounted in Plutarch's Lives: Julius Caesar (c. a.d. 110), the crossing gave rise to the figurative English usage by the early 1600s.

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Example Sentences

The Rev. Samuel Rodriguez, president of the National Hispanic Christian Leadership Conference, an association of 42,118 U.S. congregations, said Hispanic churches “are about to cross the Rubicon into thriving.”

From Washington Times

That’s a bit like writing a memo for Julius Caesar that concluded, without qualification, that “the fact is that the Roman Constitution assigns this power to you, Caesar, as the ultimate arbiter about whether to cross the Rubicon.”

From Slate

In the last two weeks of December, they pushed Trump in their protests and on social media to “Cross the Rubicon.”

From Seattle Times

From what we have learned since, some of Trump's supporters were even imploring him to "cross the Rubicon," a reference to Julius Caesar's initiation of the civil war that eventually transformed Rome into a dictatorial empire, expressing a longing to smash American systems and eviscerate the republic.

From Salon

In a way, they did cross the Rubicon, so to speak, and started describing him as a liar, and also tried to document what he was really up to.

From Salon