Once the they get an idea in their heads, nothing, not evidence, not truth, not years of data to the contrary nor decades of experience will ever alter the thinking or change the mind of the conservative. 

We have the most inefficient healthcare system in the world but we can't transition to something that works because that would be "socialism"...so we continue on with our private-insurance based debacle. We tried alcohol prohibition 100 years ago with disastrous results but drug prohibition? You bet!. Instead of considering actual solutions to our drug issues, conservatives prefer bumper sticker slogans like "just say no", "more cops, more prisons, tougher laws", "3 strikes you're out" and "war on drugs". Even 40 years of abject drug war failure doesn't make a dent. But hey, at least the drug war is the biggest workfare program in the history of mankind.  

Conservatism is the single biggest obstacle to effectively dealing with our country's problems.