The term "Speak Truth to Power" might have a noble provenance, but ever since the period of the Second Iraq War, it has been used, with all its triteness and almost cutesy grammatical oddity, to the point of being overused.
My puzzle with this advice is, why are we giving the powerful one more thing? The powerful already have enough toys to play with, and if you gave them the truth, it would just end up tossed in the corner with the exotic security derivatives, admissions to conferences in Switzerland and Singapore, or sculpture they made at Burning Man. And it isn't like the powerful can't find the truth if they wish to: presumably with all their resources, in 2018, they can figure out how to use google or wikipedia.
If you want to do something useful, go and speak some truth with the powerless, who probably need it more, and might have more access to it. And, in 2018, sometimes the "powerless" have more power than the "powerful".