On August 13, 2019, we wrote about an extraordinary Amicus Brief filed by Senator Sheldon Whitehouse (D-RI) on behalf of himself and several other Democrat Senators.
The Brief was extraordinary because it threatened the Justices with a potential restructuring of the Court if the Justices didn’t dismiss as “moot” the first big 2nd Amendment case the Court has taken in a decade. 
The Brief was panned by right, left, and center as a thinly-veiled and inappropriate threat.
...The closing paragraph was at best a thinly-veiled threat (emphasis added):
The Supreme Court is not well. And the people know it. Perhaps the Court can heal itself before the public demands it be “restructured in order to reduce the influence of politics.” Particularly on the urgent issue of gun control, a nation desperately needs it to heal.
This was not so much a legal argument, but a shot across the bow of the Court and Chief Justice Roberts in particular.
Nice Court you have there, Chief, shame if something happened to it.
On October 7, 2019, the Supreme Court refused to dismiss the case in a short-form Order, ruling that the issue of mootness should be discussed at oral argument (on December 2):
The Respondents’ Suggestion of Mootness is denied. The question of mootness will be subject to further consideration at oral argument, and the parties should be prepared to discuss it.
Whitehouse’s threat didn’t work procedurally, but it still may have an impact. 
You can’t unring that bell, and the purpose was to intimidate Chief Justice Roberts much as Obama and Democrats tried to (and arguably did) intimidate Roberts on the first Obamacare case."
Read all.