Professor Warren (I'm using the title she's earned that should get more respect than "Senator" after Thurmond and McCarthy and so many other miscreants) properly called for the "Resistance" to follow the bloody law: If they believe Trump is unfit for office, invoke the 25th Amendment. I'm actually rather pissed off that I had to go down eleven items in my search list before finding one with a non-misleading headline that doesn't miss the point entirely.
What this reflects, more than anything else, is the ahistoricity of the American media/conversation. From the 1950s until Watergate, there was a thread of fictional works that emphasized the duty of subordinate officials to follow the directives of the executive — even when they disagreed with them as policy matters — unless and until willing to pay the personal price for disobedience. Wallace's The R Document, Knebel & Fletcher's Seven Days in May (later adapted for a Kirk Douglas film), even Burdick & Wheeler's horribly mischaracterized (and overblown) Fail-Safe (either the unsatisfactory novel or the unsatisfactory film) were all part of the "national conversation" prior to Watergate, but disappeared. So, too, has the thread, as implicated in Seven Days in May itself: Now, the narrative almost always includes an immediate reward for "resistance." No one spends time in a Birmingham jail any more…
Instead, "resistance" — from the mildest speaking truth to power through active resistance up to whistleblowing — has lost the element that makes it appropriate: Perception of personal risk and the balancing act that prevents descent into anarchy. It's now as much a part of the playbook for personal aggrandizement as anything else; the rats leaving the sinking ship are demanding their fifteen minutes of fame (hoping to parlay that into a continuing slot as a pundit, which has much less risk of failure because it doesn't require the effort and expertise of actually making something happen and dealing with the unanticipated consequences) instead of doing anything to plug the leak… or prevent the next one. It's 20/200 hindsight from ignoramuses who espoused an ideologically correct policy and then discovered that policy didn't fit anything resembling facts (or even alt-facts). It's refusal to accept that Mark Felt neither sought nor obtained glory, riches, higher office, or that fifteen minutes through his acts of "resistance."
That's what Professor Warren is getting at, which you'll understand if you actually read/listen to her tweet (not linked; this blawg never links to that social media platform, but you can find it in Ms Martinez's article) or website instead of the misbegotten headlines and soundbites. Actions have consequences, and they're often mixed. That's perhaps too, umm, professorial a view for one to expect from a Senator elected in our broken two-party binary-merit system that forces us to choose the lesser evil all time because the choices we are presented are almost always evil; and, therefore, that's not what the media heard or continues to spin. The irony that so many of the commentators criticizing the oversimplistic soundbite view of Professor Warren's comment are (or at least portray themselves as) "resisters" who used that "resistance" as a stepping stone to a larger platform has escaped just about everyone.
disclosure: As a newly minted lawyer in the mid-1990s, I represented consumers in a number of class actions that were related to or going through the bankruptcy courts, and more generally in consumer finance. Professor Warren was a leading authority and provided valuable consultation on some of those matters… including, on more than one occasion, pointing out that one of the firm's dearly-loved positions was not defensible in law, but required a legislative fix if that was even possible.