Welsh poet Dylan Thomas said, “When one burns one's bridges, what a very nice fire it makes.” Living upon the shores of a distant future, each moment can be contemplated as to where one has been and where one might go, there are times when one has decided to literally burn the old bridge and sometimes writs called arson. To burn one’s bridges, or in a related idiom, to burn one’s boats, means to take some action where it becomes impossible to return. Whether it’s to destroy all chance of escape or prevent a retreat the expression began to appear in the English language as early as 1745, but the idea behind it has been around since ancient times.
Plutarch recounts part of the following story in his Lives: Julius Caesar (c. A.D. 110). In 59 BC the Roman triumvirate of Pompey, Crassus and Julius Caesar had established the Roman Empire. Four years later Crassus died bringing Pompey into direct conflict with Caesar. Roman leaders became embroiled in greed for power leading to struggles between the upper and lower classes that would eventually erupt into civil war. The Senate aspirations for terminating Caesar’s military command and defeating his second stand for consulship in 49 BC ordered either Caesar’s disbanding of his legions and his attendance in Rome at the time of the election, or his continued command and abandon his claims to the consulship. When the Roman Senate saw Caesar’s legions on the shores of the Rubicon River they drew a line in the sand saying he could not cross the river between between Italy and Gaul or it would be looked upon as a declaration of war. Determined to acquire his consulship Caesar crossed the river with purpose and a sense of mission, changing history forever. Eventually this brazen act gave rise to the figurative phrase cross the Rubicon meaning to, "irrevocably commit to a course of action, make a fateful and final decision," during the early 1600s. As many know Caesar was successful for a while, but the Senate hatched a conspiracy and murdered Caesar.
So what does Caesar’s crossing of the Rubicon have to do with burning one’s bridges? The reference is to Julius Caesar and other Roman generals of the era, who set fire to their boats or ships during an invasion. The tactic was used to not only thwart a pursuing enemy, but also to impress upon the Roman soldiers that they must either conquer or die because retreat is impossible. One consequence to this strategy was that it made a nightmare of a logistics problems for re-supplying the forces, so by today’s meanings it describes a striking gesture done that not only has the effect of preventing one from going back, but also causes other troubles.
Eventually the phrase evolved into the proverbial warning, "Be careful not to burn your bridges.” Surprisingly this didn’t appear until the late 1800’s. In 1886 Mark Twain wrote in The American Claimant, “It might be pardonable to burn his bridges behind him.” Almost thirty years later Edgar Rice. Burroughs used the expression in his Tarzan of the Apes writing, “Because she had been afraid she might succumb to the pleas of this giant, she had burned her bridges behind her.” By 1943, Perry Mason mystery writer, Earl Stanley Gardner came up with a new twist on the old proverb in his Case of Empty Tin noting, “We'll cross that bridge when we come to it.” The fall of following year the Allies initiated Operation Market Garden to try and capture the bridge over the Rhein in Arnhem. Maybe it was to prevent its destruction so they could continue their pursuit of the German army. The paratroopers had no additional support and were unable to hold the bridge. Hence operation was regarded as "a bridge too far" a phrase meaning a target that is too ambitious.
In due time the malapropism, “We'll burn that bridge when we get to it,” arose and on a related note a more modern political corruption of the phrase has appeared in Ann Coulter’s How to Talk to a Liberal (If You Must): The World According to Ann Coulter (2004). In it she lampoon’s Senator Ted Kennedy attitude towards Iraq as one of, “We’ll drive off that bridge when we get to it,” a reference to his accident involving Mary Jo Kopechne.
Sources:
cross the rubicon:
http://dictionary.reference.com/search?q=cross%20the%20rubicon
Expressions & Sayings (B):
users.tinyonline.co.uk/gswithenbank/sayingsb.htm
Free Republic:
http://209.157.64.200/focus/user-posts?id=47831
Oxford English Dictionary:
http://dictionary.oed.com.ezproxy.library.arizona.edu/cgi/entry/50027457