The al Qaeda terrorists who crashed into the World Trade Center didn't have to prove that their beliefs were right for them. However, they did have an "impact" (pardon the pun) on others.
It would be nice to talk to and dissuade would-be terrorists whose religious zeal has been warped into murder and torture.
For example, President W. Bush was elected President of the United States largely by efforts of the Religious Right (who also voted in Reagan and Bush Sr)., but W. Bush made an unprovoked attack on Iraq, killing 1,000,000 Iraqis. The Religious Right backs the National Rifle association, war, torture camps, lower tax for the rich at the expense of the working middle class (which outsourced factories abroad for cheap foreign labor), etc. In other words, by mixing politics and religion, God took second place.
It would be good to ask the Religious Right if guns, wars, torture camps, and greed are the right path for their religion. Where in the bible does it say that they are?
Religion isn't just a personal choice that has no impact on the world around them. Our Supreme Court judges were chosen by President W. Bush, and they serve life terms long into their 90's, making decisions that overlap many presidencies.
The way we handle Global Warming, pollution, taxation, education, etc. were decided by the Religious Right. Can't we ask if they were wrong to make some of their decisions?