It's hard to say when scientists realized that policy makers were not always going to make the best decisions regarding science funding but a safe bet would be somewhere before 3,000 BC.

In the intervening 5,000 years, not a lot has changed in how well scientists, politicians and the public really understand each other. A week doesn't go by when there isn't an article lamenting that one project or another doesn't get funding or that one government bureau is over-zealous or too conservative.

Scientists learned early that the best way to get the message across to the people who can truly influence policy makers was to consult them directly. In past ages it was advisors to kings.