Voting only works if both parties are willing to accept an outcome of a vote. There's usually a tipping point where a group angling for dictatorship through violent means is not going to care about whatever the outcome of a vote is once they feel they have enough ability to force any opposing group to submit through violence.

Going back to the Spanish Civil War, the conflict kicked off because the fascists attempted a military coup, as they did not like the outcome of the votes. The options left to the non-fascist factions were to either peacefully accept the new non-democratic military dictatorship, or violently oppose it.

Hitler and Mussolini both had to play the political game only up until the point they had enough military might that was both loyal and willing to follow orders (Blackshirts and Brownshirts), enabling them to threaten or kill any faction that opposed them in their respective parliaments. At that point a populace voting no longer has any effect.

We are currently witnessing the US right-wing attempting as best they can any method available to achieve that loyal military might, mostly through ICE currently, but also trying as best they can to convert the US Military and three letter agencies to become loyal arms of the regime by replacing their leaders with loyalists.

Hopefully they will fail to suppress the midterms simply due to the sheer scale of the country and the still inadequately sized ICE to cover it, but should they succeed, it is likely the tipping point will be reached, and voting beyond that point will have no meaningful effect toward slowing or preventing a dictatorship, leaving only unions, individual states resisting, etc. If the dictatorship then increases violence to try to crush those forms of resistance, and unions submit, disobedience dissolves, states cease fighting, that that would leave essentially a troubles situation along with less overt everyday resistance (slowdowns, trying to make the machine less efficient, etc).