when I was a boy in the early to mid 60's, my father (a liberal of that era) was showing me a gun of some kind that he had picked up in Germany while in the Army during WWII. It had belonged to a dead German soldier and was inoperable (correct my term but maybe had a missing/broken firing pin? I don't recall what he called the part). It seemed very cool to me on many levels, and was a surprise because I was unaware of its existence.
He showed it to me and wanted me to know where he kept it. While putting it away, he said that the Police Department of our city, a well off suburb of Boston, had asked for people who had guns in their homes to come down to the station to register them, just so there could be a record for whatever reason they cited.
But this liberal man, as honest and law abiding a person as I have ever known, told me to never give up that info. He said if we did, then the police/gov't would have no problem coming around to collect everyone's guns and there may be a time in the future that we may not be as comfortable with that particular police/gov't. Yes, even his broken German pistol, just on principle.
He wasn't necessarily making a statement about the 2nd amendment, and it wasn't because he feared either party specifically. He said it could be the opposing side going bad or our side getting too powerful, which he also warned against. Benevolent dictators are still dictators, and that we could not support in America.
Basically, he felt it was too much power for even the side of his choice to have. And WWII was barely 20 years from having ended. And his parents left a country that targeted Jews even before the first World War...history.