I watched the 2002 documentary The Weather Underground. They were a "terrorist" group in the early '70s, during the Vietnam War, a small group of youth, mostly university students, an offshoot of the SDS. I don't know if they made things better or worse, or both better and worse, or neither better or worse. But they were careful not to kill anyone---at least they were careful after that one unfortunate incident.
Some members of the group were killed when a bomb they were preparing exploded. They intended to set it off at a dance for Army NCOs somewhere. I don't know what course things would have taken if they had succeeded, if the bomb hadn't gone off prematurely, but it made them re-think what they were doing, and they decided to be very careful not to harm anyone after that. They would phone in warnings and ask that police evacuate buildings.
Police and FBI at the time were carrying out a massive program of repression and assassination against the Black Panther Party, against Martin Luther King and any other black or anti-war organization. It's surprising there weren't more groups like this.
Once the war ended, the group started to fall apart and they started turning themselves in to police. Interestingly, very few were prosecuted since the police and FBI would have to have admitted to all the laws they violated in their pursuit of them. That wouldn't be a problem for the government today---the bill of rights is no more. They can cry terrorism and do what they like.
It make me think of the European mini-series Carlos, except Carlos was perfectly willing to kill people. But they could both be accused of petit bourgeois vainglory, doing this stuff in place of serious political organizing. The Black Panthers themselves didn't think much of them. They accused them at one point of "Custerism"---of leading their people into a massacre---after they organized a little riot.
Public opinion was firmly against the Vietnam War well before the Weathermen came along, but public opinion made no difference. The war went on and on. Former Weathermen have argued that what they did didn't work, but nothing else worked, either. Hard to believe that setting off a few bombs would do the trick.