The essential point or problem is the crux. People are always trying to get to the crux of a matter or the crux of a problem, while others try to distract them.
The noun crux is often followed by the phrases "of the matter" or "of the problem." When people are trying to identify the crux of something, it's like they want to get to the heart of it. They want to peel back the layers and find out what something is really all about or what is causing the problem. No more beating around the bush!