So you are actually saying that a duly elected government body can not change laws within their own country?
Germany was governed by a constitution, right? Let's first agree upon that. I don't think that's really debatable.
Now, under the provisions of the Enabling Act, which was legislatively approved, Hitler banned several political parties, yes? Again, not really debatable.
Here are the key parts of the Act:
Die von der Reichsregierung beschlossenen Reichsgesetze können von der Reichsverfassung abweichen, soweit sie nicht die Einrichtung des Reichstags und des Reichsrats als solche zum Gegenstand haben. Die Rechte des Reichspräsidenten bleiben unberührt.
The office of the president and the Reichsrat were not to be abrogated constitutionally. Unfortunately, in declaring himself Reichspräsident in 1934, rather than conducting an election, Hitler violated the constitution
and the Enabling Act. Furthermore, Hitler had also dissolved the Reichsrat, which was in violation of both the constitution
and the Enabling Act.
Let's continue:
Dieses Gesetz tritt mit dem Tage seiner Verkündung in Kraft. Es tritt mit dem 1. April 1937 außer Kraft, es tritt ferner außer Kraft, wenn die gegenwärtige Reichsregierung durch eine andere abgelöst wird.
Hitler was supposed to have the law reviewed by April 1, 1937, or cede dictatorial power. At that point, besides already having violated the constitution by declaring himself president, Hitler was ruling without constitutional authority after April 1, 1937. (I.e., the law was only good for four years.) In short, after April 1, 1937, Hitler was no longer ruling Germany legitimately.
But consider this also: Hitler had already had the KPD deputies arrested. That being the case, and given the KPD's opposition to the Enabling Act, given that the KPD was the third largest party in Germany, and given the use of the SA on the day of the vote, it's quite possible that the vote for the Act itself was illegitimate and unconstitutional.
All that being said, the argument for the banning of the SPD having been "legal" is pretty weak.
And let's add to the mix.. citizenship laws.
Was Germany within their right to change citizenship laws?
Of course, but it was done in 1935, when parties had been banned and, therefore, there is some question as to whether these laws would have remained in effect after April 1, 1937, when Hitler was constitutionally bound to re-convene the Reichstag.
Furthermore, the very language of the acts in 1935 that re-defined citizenship were passed, they were done in language that did not alter or amend the constitution, which means that, after April 1, 1937, they lacked force of law.
When are you guys going to get that Nazi Germany was an illegitimate state for most of its existence?