Prior to Hitler, German soldiers made the following oath:
I swear fidelity to the constitution of the empire, and vow that, as a brave soldier, I will at any time protect the German Reich and its regular institutions... (source)On February 8, 1934, that oath changed from fidelity to the constitution to loyalty to one man:
I swear to God this sacred oath that to the Leader of the German Empire and people, Adolf Hitler, supreme commander of the armed forces, I shall render unconditional obedience... (source)No longer were soldiers committed to defending the constitution. The constitution had become a meaningless rag.
Prior to Hitler, civilians were not required to recite any loyalty oath. As of 1934 they were:
I swear: I will be faithful and obedient to the leader of the German Empire and people, Adolf Hitler, to observe the law, and to conscientiously fulfill my official duties... (source)Some Germans refused to swear an oath to a person instead of their country's constitution. Many of these were executed or sent to concentration camps.
On taking office as director of the FBI, James Comey took the following oath:
I, James Comey, do solemnly swear that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter. So help me God. (source)The FBI, in their own website, says that loyalty oaths to individuals "too easily leads to tyranny on the one extreme or anarchy on the other."
Trump's expectation of personal loyalty over loyalty to country strikes at the very heart of our freedoms.