Unfortunately, that strength of principle and correctness of judgment, which might enable him to resist the various seductions to which his fame and rank exposed him in the metropolis of the Union, were not associated with the firmness which he had displayed in the field, and in the most adverse circumstances.  Yielding to the temptations of a false pride, and forgetting that he did not possess the resources of private fortune, he indulged in the pleasures of a sumptuous table and expensive equipage, and soon swelled his debts to an amount which it was impossible to discharge.  Unmindful of his military character, he engaged in speculations which were unfortunate; and with the hope of immense profit, took shares in privateers which were unsuccessful.  His claims against the United States were great, and he looked to them for the means of extricating himself from the embarrassments in which his indiscretions had involved him; but the commissioners to whom his accounts were referred for settlement, had reduced them considerably; and, on his appeal from their decision to congress, a committee reported that the sum allowed by the commissioners was more than he was entitled to receive.

He was charged with various acts of extortion on the citizens of Philadelphia, and with peculating on the funds of the continent.  Not the less soured by these multiplied causes of irritation, from the reflection that they were attributable to his own follies and vices, he gave full scope to his resentments, and indulged himself in expressions of angry reproach against, what he termed, the ingratitude of his country, which provoked those around him, and gave great offence to congress.  Having become peculiarly odious to the government of Pennsylvania, the Executive of that state exhibited formal charges against him to congress, who directed that he should be arrested and brought before a court martial.  His trial was concluded late in January, 1779, and he was sentenced to be reprimanded by the Commander-in-chief.  This sentence was approved by congress and carried into execution.

From the time the sentence against him was approved, if not sooner, his proud unprincipled spirit revolted from the cause of his country, and determined him to seek an occasion to make the objects of his resentment, the victims of his vengeance.  Turning his eyes on West Point as an acquisition which would give value to treason, and inflict a mortal wound on his former friends, he sought the command of that fortress for the purpose of gratifying both his avarice and his hate.[42]

[Footnote 42:  The author is informed by General Lafayette that Arnold, while commanding at West Point, endeavoured to obtain from General Washington the names of his secret emissaries in New York, and his means of communicating with them.  He pressed Lafayette, who had also his private intelligencers, for the same information.  His applications were of course unsuccessful.  It cannot be doubted that his object was to commit the additional crime of betraying them to Sir Henry Clinton.]