This is a good article about influence and mormons pushing Reid over the top.
http://blog.beliefnet.com/religionandpubliclife/2010/06/reids-mormon-support.html
I’ll keep looking for the links about Reid and percentage of mormons who support him.
I am not sure if you are aware/care, Reid is a temple worthy mormon, only 15% or so reach that high level. He has also received awards from BYU for being a good example of what a mormon should be.
At his meeting with Mormon business leaders, they heckled and booed him. One of his campaign events at a Mormon church was canceled because they objected.