I am sympathetic to this but I have dealt with very senior candidates that could not demonstrate any coherent thought about a given problem over a whole intervi

I am sympathetic to this but I have dealt with very senior candidates that could not demonstrate any coherent thought about a given problem over a whole interview. Others don't get code done but at least they can express a clear understanding of the problem and have an intelligent conversation. I don't care if they can write the code but I want to see some level of engagement with the problem and some understanding.