Forty-one percent of Biden supporters say they believe people who support the Republican party and its ideologies have become “so extreme in what they want that it is acceptable to use violence to stop them from achieving their goals.” Likewise, 38 percent of Trump supporters say it is OK to use violence to stop Democrats from achieving their goals...
A significant share of respondents question if democracy is no longer a viable system of governance; 31 percent of Trump supporters said America should explore alternative forms of government to ensure stability and progress, compared to 24 percent of Biden supporters.
I wish I could remember the name of it (or Google was less shit) but there was a study done a few years back that showed both centrist voters and politicians had much less belief in and much higher distrust of democracy than either the right or the left. It was called something like 'the extreme centre' but I can't find the original study.
Try Google scholar?