My guess is that some protestors will try to duplicate 1998, i.e., create enough disturbance to associate the Republican Party with chaos, disorder, and trouble, so that voters vote Dem in order to "make it [the chaos] all go away." But it might backfire if they do this; voters might accurately perceive that the disorder and chaos are coming from forces sympathetic to the Dems.
duplicate 1998 - of course I mean 1968.
But the Republicans won in '68.