cross the Rubicon

Related to cross the Rubicon: passed the Rubicon

cross the Rubicon

To commit to a particular plan or course of action that cannot be reversed. The phrase refers to how Julius Caesar crossed the Rubicon river and became embroiled in civil war in 49 BCE. Look, if you cheat on this test, you are crossing the Rubicon, man. You can't take that back. I think I crossed the Rubicon when I took this management position. It would be a huge pay cut to go back to my old job, and my boss would be furious.
See also: cross, Rubicon
Farlex Dictionary of Idioms.

cross the Rubicon

Fig. to do something that inevitably commits one to following a certain course of action. (Alludes to the crossing of the River Rubicon by Julius Caesar with his army, which involved him in a civil war in B.C. 49.) Jane crossed the Rubicon by signing the contract. Find another job before you cross the Rubicon and resign from this one.
See also: cross, Rubicon
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

cross the Rubicon

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.
See also: cross, Rubicon
The American Heritage® Dictionary of Idioms by Christine Ammer.

cross the Rubicon

FORMAL
If you cross the Rubicon, you make an important decision which cannot be changed and which will have very important consequences. Today the Government has crossed the Rubicon in favour of the Euro. In England and Wales the Rubicon has been crossed regarding the charging of fees to students. Note: This expression is variable, for example people sometimes talk about the crossing of the Rubicon or a crossing of the Rubicon. Such a decision would be a crossing of the Rubicon. Note: Sometimes this important decision is referred to as a person's Rubicon. There would be no turning back; if he was making a big mistake, this was his Rubicon. Note: The Rubicon was a small river which separated Roman Italy from Gaul, the province ruled by Julius Caesar. Caesar crossed the Rubicon in 49 BC, invaded Roman Italy, and started a civil war. `The die is cast' is based on the same incident.
See also: cross, Rubicon
Collins COBUILD Idioms Dictionary, 3rd ed.

cross the Rubicon

take an irrevocable step.
The Rubicon was a small river in north-east Italy which in the first century bc marked the boundary of Italy proper with the province of Cisalpine Gaul. By taking his army across the Rubicon into Italy in 49 bc , Julius Caesar broke the law forbidding a general to lead an army out of his own province, and so committed himself to war against the Senate and Pompey.
See also: cross, Rubicon
Farlex Partner Idioms Dictionary

cross the ˈRubicon

(formal) reach a point where an important decision is taken which cannot be changed later: Today we cross the Rubicon. There is no going back.The Rubicon was a stream which formed the border between Italy and Gaul. When Julius Caesar broke the law by crossing it with his army, it led inevitably to war.
See also: cross, Rubicon
Farlex Partner Idioms Dictionary

cross the Rubicon, to

To take an irrevocable step. The term dates from 49 b.c., when Julius Caesar crossed this river between Italy and Cisalpine Gaul, thereby invading Italy and disobeying Pompey and the Roman Senate. The Senate, he had learned, intended to disband his army, whereupon Caesar joined his advance guard on the Rubicon’s banks and told them, “We may still draw back, but once across that little bridge we will have to fight it out.” The term has been a cliché since about 1700.
See also: cross
The Dictionary of Clichés by Christine Ammer
See also:
  • cross the Rubicon, to
  • Rubicon
  • pass the Rubicon
  • the die has been cast
  • the die is cast
  • die is cast
  • die is cast, the
  • beware the ides of March
  • et tu, Brute?
  • Tu
References in periodicals archive
"The expectation is that the rank and file won't memorize everything but they'll get sensitized to it enough so that they understand that if they see something that could be an issue, they'll stop before they cross the Rubicon and bring the issue up with the right people."
If the pope would truly like to cross the Rubicon to the green side, perhaps he should consider canonizing Thomas Berry instead of "bundling popes." Berry, in his The Dream of the of the Earth, states: "We come to the essential problem of economics as a religious issue when we consider that the present threat to both economics and religion is from a single source: the disruption of the natural world.
September 26 Advancing up the Italian boot, British Eighth Army units cross the Rubicon River.
Possibly we are about to cross the Rubicon in electoral politics in Africa.
(While the implications of this rising trend are left to the reader, nowhere does the book imply that our combatant commanders are present-day Caesars, about to cross the Rubicon and seize Rome.) The last chapter of Reveron's book expertly examines their rising power and influence on traditional civil-military relations.
"On Wednesday, the thirteenth day of October in the year many people call 49 B.C., Caius Julius Caesar, a Roman general, crossed the ancient watery boundary between Cisaplin Gaul and Italy known as the River Rubicon, thus making immortal the phrase "to cross the Rubicon," meaning "to take a decisive and irrevocable step."
We may cross the Rubicon in less than ten years, according to the Institute for Public Policy Research, the Centre for American Progress and the Australia Institute.
To cross the Rubicon under arms and march on Rome to seek the consulship was therefore a flagrant violation of multiple legal and political conventions, in a society where law, tradition, and precedent still mattered a great deal.
Yet I still can't cross the Rubicon. I cannot hate the English.
"Parliament is not being asked to cross the Rubicon today."
Marcus: But, sir, it is illegal for you to cross the Rubicon with your men.
TWO horses have been doubly declared today: Cross The Rubicon - First pref Plumpton 4.30; Second pref - Market Rasen 5.00.
Thus Caesar's decision to cross the Rubicon was a free act because its cause was internal to Caesar, it was contingent for us, because we cannot perform the infinite analysis to discover within the complete idea of Caesar the predicate that was this action; and it was necessary, both because the complete idea of Caesar does contain this predicate, and because in the best of all possible worlds everything is determined.
In December, EU countries will cross the Rubicon in defense with a major new initiative on capabilities, security research and force projection.
When the recommendations were published, David Cameron spoke against using statute to underpin regulation, saying it would "cross the Rubicon" after centuries of press freedom.