I think American politics today can be broken down as follows:

There are three main groups in America today: revolutionaries (we'll call them progressives), reactionaries (we'll call them conservatives), and the supporters of the status quo (we'll call them centrists).

The centrists are people who are generally doing well, are generally happy and content, and therefore don't want things to change significantly. They might be willing to accept relatively minor changes, but only if the changes don't negatively impact them in any meaningful way.

Progressives are people who are generally unhappy and discontent. They don't feel that things are working for them, so they want to radically change things, in the hopes of making society more like their hypothetical or theoretical ideal.

Conservatives are generally a reaction to progressives. Like progressives, conservatives aren't entirely content with the status quo, but they generally blame progressives for any problems. They believe it was progressives who created the problems when they tried to make radical changes, and conservatives therefore think the best way to solve the problems is to roll back any of the changes and to just generally go back to a better, more stable, more traditional past.

Progressives hate the centrists, for their opposition to the radical changes they propose, changes that progressives view as absolutely necessary. Progressives feel that the centrists lack empathy, as they are unable to see, or don't care, that progressives are very unhappy and discontented, and may even be suffering.

The centrists see progressives as overly idealistic malcontents who are simply blind to how good they have it and to all the status quo has given them. The centrists also resent the progressives for asking them to make sacrifices. The centrists believe they earned their success, and there's no reason to punish them for it, and that progressives are just “sore losers.”

Conservatives absolutely hate progressives, with a murderous rage. They hate that progressives want to radically change things, and they hate that progressives reject tradition and established hierarchies/hegemony. conservatives are infuriated that progressives won't show deference to traditional authority, and even dare, in some cases, to call for the destruction of said authority.

Conservatives don't necessarily like the centrists either, but any problems they have with the centrists comes down to any willingness they may have to work with progressives. For instance, if the centrists are ever willing to listen to or compromise with progressives, conservatives view that as total capitulation to the progressives, and/or the status quo being completely co-opted or infiltrated by progressives.

Conservatives now believe that the status quo has been taken over by progressives, and thus they make no distinction between the centrists and progressives, viewing both as the enemy. Therefore, it has become necessary for the centrists to ally with progressives (as much as they might hate that thought) against conservatives. However, the alliance is restricted only to opposing conservatives, and does nothing to change the centrists’ general opposition to the aims and ambitions of progressives. For this reason, progressives are reluctant to form an alliance with the centrists, since they believe the centrists are asking for the progressives’ help without offering anything in return. The centrists argue that they don't have to offer anything to the progressives, and that the progressives should help the centrists because it is also in their interest to see the conservatives defeated.