We frequently hear the some large percentage of the public is in support of universal background checks for firearms sales. But it is easy to demonstrate that a large percentage of the public is either ignorant of the effectiveness of background checks or has evil intent.
Basically the problem boils down to a large percentage of the public has opinions on things they really don’t know much about. Brother Doug pointed out a great example recently:
A … survey in January conducted by the Oklahoma State University Department of Agricultural Economics found that 82 percent of respondents supported mandatory labels on GMOs. However, 80 percent of respondents also said they supported mandatory labels on “foods containing DNA.”
This is the reason we have a representative democracy with enumerated powers for the government rather than a direct democracy. Our representatives are supposed to carefully study and debate any potential laws and only enact laws that are beneficial to the majority of people and do not infringe upon the rights of anyone.
Popular opinion can easily be shown, see above, to be a very poor way of determining, well, almost anything.