The problem in all this is the history of Nazi Germany. To use the term brownshirt today invokes images of SS troopers. But the real Brownshirts, or SA, were just men who were fanatical followers of Ernst Rohm. Rohm in turn had chosen to support Hitler, but for a price. When Hitler became chancellor thanks to the strong arm tactics of Rohm's men, Rohm then began pushing for more power including the replacement of the Army with his men. Eventually Hitler, who had no intension of sharing power with Rohm, had no choice but to act and June 30th, 1934 Hitler personally arrested Rohm and over 200 of the leaders within the SA. The following day Rohm told Hitler he wouldn't commit suicide and was then killed by two SS troopers. By that time over 80 of the other arrested SA members had been killed- some estimates are that all were eventually executed. Its new leaders were then selected by the Nazi party and the organization was greatly reduced in power and size (many of the younger men forced to join the Army following the start of the war).
The point of this discussion: in 1968 the Democratic party held its presidential convention in Chicago. Earlier in the year Black activists and citizens had come out in a riot following the death of Martin Luther King. This and the protest at the pentagon prompted a slew of young, politically inspired, students to show up for the convention. Modern histories try to pain the "Hippies" as peaceful or even enlightened. The reality was quite a few came ready for a fight, a fight that became all the more their plan when the hordes of protesters the leaders expected didn't materialize. In the end members actually hoped they would force mayor Dailey to declare martial law (to reinforce their views).
Now the Democratic party has formed groups even more radical then the ones in 1968. Will they stay away from the planned presidential convention and allow it to go forth without incident. Or will they show up to demand their share of power, particularly since many support Bernie Sanders who is rapidly being denied the nomination by the Democratic party's undemocratic policy of super delegates. To see them using Nazi tactics to silence Donald Trump is actually expected. But equally expected is to now see them show up for their payment for services at the pending Democratic convention. And thus, when will the Democratic party decide these groups are more trouble then they are worth.