Sedition and treason are two different but related concepts/offenses. Sedition is plotting to overthrow the government or encouraging other people to do so. Treason is waging war against the country or helping a war-time enemy. Both can be federal crimes. And a seditious conspiracy can potentially lead to an act of treason if the plot is undertaken.

Here is the law against seditious conspiracy https://www.law.cornell.edu/uscode/text/18/2384

> If two or more persons in any State or Territory, or in any place subject to the jurisdiction of the United States, conspire to overthrow, put down, or to destroy by force the Government of the United States, or to levy war against them, or to oppose by force the authority thereof, or by force to prevent, hinder, or delay the execution of any law of the United States, or by force to seize, take, or possess any property of the United States contrary to the authority thereof, they shall each be fined under this title or imprisoned not more than twenty years, or both.

That says "seditious conspiracy", not "sedition". I'm not saying it's wrong to call that "sedition" by extension, if you like, I'm just confused because I didn't get the memo on how the word is being used now.

All my life, "sedition" has meant, as far as I knew, criticism of the government, possibly false criticism. Nor did I know of laws against it since around a hundred years ago or more.

Here is something saying sedition is:

"The federal crime of advocating insurrection against the government through speeches and publications."

https://www.law.cornell.edu/wex/sedition

Here is a part of the law that sounds like it's outlawing sedition even though it doesn't actually include the word: https://www.law.cornell.edu/uscode/text/18/2385

The significance, ultimately, is I'm suspicious that someone is pushing this term because they want to turn around and outlaw criticizing the government and say Democrats asked for it. Or, even if nobody has that plan yet, that using the term carelessly could invite it.

Based on this definition (and ignoring others such as enumerated duties) the Congress has been involved with seditious conspiracy whenever they block passage of a bill. However, since that is part of the job, it's ok. What is NOT ok is for elected officials to incite dissent and encourage blockage of government functions... which many Democrats have been doing in the same way Trump did (via Twitter) for longer than we have had Trump. And which also let to riots with violence, along with occupying and/or destruction of federal and state buildings and property. And encouraged - praised! - by the very politicians crying about it today.

>Is sedition illegal? Should it be?

How are we defining sedition though? Rebelling against society is one thing. I'm an old punk rocker. Did I break laws I didn't agree with? Yes, repeatedly. But I also accepted that, right or wrong, it was my personal choice, I made those decisions myself and if I faced consequences for it they were my consequences to face, not someone else's. There's a difference between sending a message and killing the messenger. I get the over all point you're making but damn what do we call it? This is way past protesting or rebelling against the government and society. We poked the bear but we didn't burn down the entire forest just to spite the bear.