It doesn't really matter to sitting Republican Reps and Sens if they lose in subsequent elections. Their fortunes are made by toeing the CofC and the Democrat line while serving. One term and a loss guarantees the Representative a wealthy lifestyle for the rest of his life so long as he voted "correctly" in his two 2 or 6 years in office. As a principled statesman he has only the income from his salary. That's not peanuts but there is ever so much more available if he just plays the game.
There is an invisible political party - government. It is a caucus with real goals, focus and power. It will always work to elect its supporters. Ike’s worry about complex didn’t go far enough.