I think it's outrageous if a historian has a 'leading thought' because it means they will select their material according to their thesis

It would behoove you to have your thesis finely tuned and the logical arguments utilized in support of it tightly woven into a credible, and creatively persuasive tapestry.

He held up his hands in surrender. “I’m not here to start trouble. I am just doing some research for my thesis.”“If you don’t get out of this bar, you are going to be writing your thesis via Ouija board.