Let me tell you a bit about Nazi Germany and Adolf Hitler.
The terror machinery of Nazi Germany and its attempt to implement the "Endlösung" led to the deaths of six million Jews and ten million Slavs. This systematic slaughter was paralleled only by Mao Zedong and Josef Stalin and led to the coining of the term genocide (genos means "race" in Greek, cide means "killer" in Latin). The Jews call it simply "Destruction"; the Romas "Devouring". It was undoubtedly one of the most evil acts perpetrated by man and the Lord willing he shall never forget it.
It came from a regime which was, in many ways, evil made solid and put in charge of a nation. In the period 1933-37 the NSDAP (Nationalsozialistische Deutsche Arbeiterpartei, or National Socialist German Workers' Party) gradually took charge of all influences over the German people by their policy of "alignment" (Gleichschaltung). Paul von Hindenburg, who had beaten Adolf Hitler in the 1932 run for Presidency (Reichspräsident) appointed Hitler to the position of Chancellor of Germany in 1933 after the NSDAP achieved a large plurarity of seats in the Reichstag (German parliament). It's a common fallacy that Hitler was elected, but he wasn't. And even before he seized power (which I'll get to in a minute) his influence was eroding the liberties of the German people and furthering his Party's ideology because Hindenburg was lapsing in and out of senility and Hitler was the real "power behind the throne".
On February 27, 1933, the Reichstag suffered an arson attack, and known Communist agitator (and ideological enemy of the Nazis) Marinus van der Lubbe was found near the scene of the crime. Many historians now think the Nazis carried out the attack themselves as justification for what followed, but there is no evidence either way. What followed was the Verordnung des Reichspräsidenten zum Schutz von Volk und Staat or "Decree of the Reich President for the Protection of People and State". Under the pretense of protecting the people, the decree destroyed their human rights: including the right to habeas corpus (the right not to be imprisoned without trial), freedom of speech, freedom of assembly, freedom of the press and the freedom to communicate without the government listening. This new power was zealously exercised by the Sturmabteilung ("stormtrooper"s) against Communists and other political enemies of the Nazi Party, and many were not allowed to retake their seats in the Reichstag after the 1933 legislative elections.
After the Sturmabteilung had imprisoned, intimidated or killed a great number of anti-Nazi legislators, a two-thirds majority was achieved for the passing of the Enabling Act (Ermächtigungsgesetz)1. This Act allowed the executive to ignore and change the Weimar Constitution and to publish legislation in the "Reich Law Gazette" without reference to the Reichstag (although the Nazis continually tried to make their regime look as legal as possible by using the legislative branch when they could). After the law was passed, other political parties were outlawed and a law was passed on July 14, 1933 which outlawed the formation of any new parties. Between then and the Night of the Long Knives, decrees were published which centralised power in the executive and at the federal level at the expense of the power of the localities.
The Night of the Long Knives was a purging of the Sturmabteilung leadership following fears by leaders of the German Army that their influence and power would be lost as the Sturmabteilung expanded their own power. Most notable among the dead was Ernst Röhm, leader of the Sturmabteilung and a personal favorite of Hitler. The Chancellor needed to maintain the support of the regular Army and so he was compelled to take this measure. The Night was legalised twenty seven days after it occured by the "Law Regarding Measures of State Self-Defence" (Gesetz über Maßnahmen der Staatsnotwehr). It consisted of a single article which read -
"The measures taken on June 30, July 1 and 2 1934 in order to put down attacks of high treason shall be legal State self-defense."
Several days later came Hitler's final grab for power. The Reich President died on August 2. Convieniently, the government had passed a law three hours prior to his death that would merge the offices of Reichspräsident and Reichskanzler (what Hitler was) on von Hindenburg's death. The new ruler would be (and the law said this exactly), Führer und Reichskanzler Adolf Hitler. Hitler was now Head of State and Head of Government, and the Nazi Party's ascendancy and his ascendancy within it was complete.
Gleichschaltung was an example of the Orwellian use of language that totalitarian regimes practice. Gradually the whole of society was being "Nazified", but people would say they had been gleichgeschaltet ("re-aligned"). By hiding behind this word the people in power could hide the true nature of what they were doing (subjecting people to physical violence and intimidation) and the people could accept it. In practice it meant subjecting every organisation in the country to Nazi leadership and removing anyone of non-Aryan descent from it (being "Aryan" essentially meant having four Gentile grandparents). A portion of the German nation had sanctioned what was going on in the 1930s, out of nationalism, anti-semitism and frustration.
It was Hannah Arendt who first coined the term "totalitarian" when she was describing the similarities between Stalinism and Nazism. The conventional wisdom used to be that these were polar opposites (one of the extreme left, one of the extreme right), but this is incorrect: both sought to control both the body and the soul of their victims, a goal they attempted to achieve through physical violence (a "cure") and propaganda (a "prevention"). Both are varieties of statism, distinct from libertarianism. Hitler boasted of how the business community thought it retained control of itself, but "our socialism goes to a deeper level": ultimately it was all controlled by the State. Outwardly, Nazi ideology opposed Marxism, but such was the regulation of industry that the State controlled all. Just like it controlled every aspect of life by the end of the 1930s: cultural, economic, political, spiritual.
There is a massive difference between patriotism and National Socialism. The sort of extreme nationalism espoused by the Nazi Party was based on the premise that a multicultural nation was a divided one. Democracy was for this reason inherently flawed because it was vital a nation not be divided: democracy gave minority groups power, and this was unacceptable. Great nations (literally "large" ones) were the end result of great races, and the Aryan race was great and deserved a great nation. They needed "space to live" or Lebensraum (Mein Kampf notes that eventually Germany would be too small to hold the entire Aryan race, hence expansion was needed). They were perfectly justified in taking this from lesser races. The annexation of Austria (Anschluss) was part of Nazism obssession with uniting all the German-speaking peoples under one nation, as language unified people and the race. People without homelands were held to be "parasites" (hence the hatred of the Jews and Romas), and if they were rich they were particularly nasty parasites. Anti-semitism dated back centuries and the first anti-semitic political parties came into being in the late decades of the nineteenth century, being the first parties that could unify most people in a nation on a single issue. Race was the driving factor behind Nazi ideology, as was hatred of any religion which preached love and compassion.
I've described a bit about the violence which brought the Nazi regime to power, the ideology behind it, and the tragedy it wrought. If you still think a comparison to modern America is justified, I won't attempt to reason with you further. But please remember, that last century, democracy truly did fail, and millions died. I thank you for your vigilance in this century.
1. Its full name was Gesetz zur Behebung der Not von Volk und Reich , "Law in order to remedy the misery of the people and the Reich." | 
