Civil service can be a thankless profession. The pay is often eclipsed by the private sector, citizens complain about perceived laziness, and privacy takes a backseat to accountability. Nevertheless, for a state to exist and function, it depends on civil servants; from dogcatcher to police officer to Senator, the efficiency of a state and its functions are only as good as its employees.
In the days of absolute rule, civil service was usually delegated to members of the privileged classes. The Romans had a tax collection system where the prospective tax collector would pay a deposit to the state, then provide the remainder of the agreed-upon amount of taxed wealth to the state while being able to hoard any excess amount for themselves. This was an incredibly profitable venture for those able to secure their contracts; a similar system was in place in France prior to the French Revolution, where nobles were assigned administrative titles explicitly as a privileged source of income. Royal attempts to revoke these privileges and increase the efficiency of the state while decreasing the budgetary deficit were a direct cause of the initial phase of the Revolution.
For a substantial amount of time the United States of America had a very similar method of appointing government officials. Known as the Spoils System, this institutionalized quid-pro-quo encouraged politicians to take a public stance for private gain. Administrative capacity took a backseat to political expediency, and organizations such as Tammany Hall and the Chicago Political Machine held great sway on American politics. This system was gradually dismantled on the federal level with a series of administrative reforms in the wake of President Garfield's assassination by a man denied an administrative office; unfortunately, it continued at the state level for quite some time, with serious discussion ongoing if it ever truly stopped.
It is here that a distinction must be made between the interests of the state and the interests of a person; the state exists first and foremost to maintain order in its domain, and though the methodology of maintaining this order has changed over time, the need to maintain order in the domestic and foreign spheres is of paramount necessity for a state. The person does not need to make order a priority; most often, survival was the first priority. And occasionally, survival is separate from order. Similar to how a prisoner might try to burn down a prison to escape, an individual may try to burn down a government to avoid prosecution.
Corruption is always harmful; every dollar put into a program for political expediency is a dollar not put into an objectively efficient program. But the scope of this harm is dependent on the breadth of responsibility of an office. A state Senator bought off by a private entity is problematic, but not as problematic as a federal Senator being bought off. Similarly, a Governor being blackmailed by a foreign power is dangerous, but not as dangerous as the President being blackmailed by a foreign power.
The office of the President of the United States of America is supremely powerful; no other position can boast the firepower or gravitas that comes with the Oval Office. Great and loathsome men alike have occupied it, but the destructive capacity of nuclear warfare was not in their hands until 1945. Since then, the ability to make humanity extinct through atomic apocalypse was in the hands of the President. This is in itself terrifying; what is more terrifying is the prospect of such responsibility being placed on someone who does not have the best interests of the state at heart.
With such sobering consequences to consider, it is vitally important for the United States of America, the world, and humanity itself that the President of the United States of America be immune to corrupt influence. This was recognized in America's earliest days - Article 1, Section 9, Clause 8 of the United States Constitution forbids members of the government from receiving titles, offices, or rewards from foreign or domestic sources without explicit permission from Congress. The importance of keeping American politicians separate from outside influence was reinforced in George Washington's farewell address, where he warned that political parties would eventually drive Americans to affiliate more with foreigners of similar ideology rather than their own countrymen.
These high stakes require a vigorous vigilance from politicians, and by extension of democratic power, from citizens. In order to keep the Republic pristine from corruption, the most powerful member of it must be held to the highest standard. Laws without punishment for transgressing those laws are less than useless. What punishment is adequate for endangering the country, the world, and the very species because of greed and self-interest?
Traitor is a heavy word. It has been interpreted many ways throughout history, but has generally lead to the same end - execution. Be it the Banu Qurayza put to death by Muhammad in Medina, shell-shocked soldiers put against a wall on the Western Front or Nathan Hale strung up by Redcoats, the state's necessity to maintain order conflated punishment for perpetrators and discouragement for future rebellion.
Benedict Arnold is the foremost traitor in American history, but he can only be considered guilty of treason because he assisted the enemy in a declared war. If Arnold did what he did while the country was at peace, he would still be considered a traitor, but he would not be guilty of treason; the Constitution is explicit about this in Article 3, Section 3. But he would still be considered guilty of espionage, which, like treason, can be punished with a death sentence. Julius and Ethel Rosenberg are the foremost examples; convicted of giving nuclear secrets to the Soviet Union, they were executed by the electric chair dubbed "Old Sparky" at Sing Sing prison. The fact that the United States and the Soviet Union were not at war did not preserve them.
Vidkun Quisling serves as another example. A former defense minister for Norway, Quisling assisted the German invasion of Norway by feeding faulty information to the Norwegian military while broadcasting a coup attempt over the radio. Later installed as the Minister President of Norway by the Nazi regime, Quisling assisted their campaigns of genocide. He would not long outlast the war; Norway would undergo a purge of Nazi collaborators, culminating in Quisling's execution by firing squad.
Legal definitions of being a traitor notwithstanding, it is in the Republic's inherent interest that its chief executive be independent of undue influence. The possibility of a war starting because of a bribe or blackmail is additionally terrible because wars frequently expand to a scope not expected by initial belligerents; World War I is the prime example of involuntary escalation. This terror is enhanced by the aforementioned nuclear arsenal that lays dormant, but remains ready to initiate Armageddon. What greater priority exists? What crime is more deserving of the death penalty, not only as punishment for a corrupt President, but to deter future Presidents from treading down this dangerous path?
If accused, tried, and found guilty of treason or espionage, the Commander of the Armed Forces should serve the same punishment as the lowliest draftee. What that means is up to us.