In perhaps one of the most famous attempts to establish scientific truth through the government, the Indiana Legislature tried legally to establish the most accurate value of pi in 1897 with the Indiana Pi Bill.
It was proposed by Rep. Taylor I. Record, who introduced it under the long title, “A Bill for an act introducing a new mathematical truth and offered as a contribution to education to be used only by the State of Indiana free of cost by paying any royalties whatever on the same, provided it is accepted and adopted by the official action of the Legislature of 1897.”
Despite its name, the main focus of the bill was to find a method to square the circle (the impossible task of constructing a square within the same area of a given circle), rather than to establish an actual value for pi, though the bill did dictate values for π, now known to be incorrect.
The bill never became law, due to the intervention of a mathematics professor who happened to be present in the Legislature.