They are not as 'spineless' as they are 'conniving'. And they are born to 'lose', not to lead.
Many Republican politicians recoil from any kind of decision or responsibility the same way a Holloywood vampire reacts to a cross. They hate responsibility. They run from responsibility. That is why they love to lose. Let the Democrats rule, and they will just follow. That is exactly where they are the most comfortable. That is what they are used to. That is what they want.
In jail, there is a term called a 'crash test dummy'. This is a person who is built up and egged on by people smarter than him to take charge. The way it works is everyone around him continuously complains about somebody, a guard of another inmate. You keep asking him, What are you going to do about this!? Eventually, the pigeon will get the idea that he has an obligation to act. And when he does, he takes the fall, punishment and more time, and all the rest of guys who made it happen get nothing, but they achieve their goal.
That is the way Republicans use the Democrats. They want the Democrats to be in the leadership positions. Then the Republicans can encourage and approve everything they do, while denying any involvement in it.
This gets turned upside down when Republicans are put in charge. All of their instincts are telling them to duck and run for cover, but now they can't, and therefore they don't know what to do. So, they choose to do nothing until they can restore the natural order of Congress and the Democrats regain control.
Every time the Democrats are running things, everything the Democrats want always gets approved. Every time the Republicans are in control, the government grinds to a halt. And that is exactly what we have seen for the last six months.