You could ask politicians how much they've researched various questions and (in detail) how thoroughly they've considered alternative possibilities.
There are lots of interesting questions that I would like to be able to force politicians to answer truthfully. I'm just not sure that any answer would matter to the politician's political followers.
I have just received a survey questionnaire regarding future directions in EU (European Union) research funding, and thought it would be interesting to see how LessWrong would answer the main question:
Imagine that EU funding is available for one ambitious, visionary project extending beyond 2020.