For example, in order to solve the middle east conflict you have to meet the valid interest of each party. However, it seams some on each side want only to dominate the other, destroy the other, and revenge past wrongs. 

These are obviously "less valid" interest, for those who want long lasting peace, who and want mankind to inhabit the galaxy. 

On the other hand, the desire to provide for your family, to live your life in freedom are more valid than the desire to dominate others. 

Reason demands that we: 

1. Identify valid interest, 

2. Conduct a thorough, open, on-line cost benefit analysis for each policy to maximize the outcomes that support the valid interest of each party

In order for this to work we must outline, for each policy or problem, the likely interest of each party. Then you simply create a scoring mechanism to rank interest validity. 

Believing something is logical is the only valid reason to support it. Observation teaches us that conflicting groups have a mix of valid and invalid interest. Good policy is simply identifying valid interest for each effected group, and selecting policies that maximize benefits associated with valid interest of the involved parties.  People support things for all sorts of invalid reasons. 

For example people seek to have psychological moral clarity. They want to oversimplify everything into black and white and good and evil. 

Evolutionary psychology enplanes why we divide the world into us and them. We form groups and have political party affiliation. We defend our guy when they do the same thing as the other side, because they are our guy. Its the same thing when we watch sports. The ref only makes bad calls against us. And when they make a bad call against the other side, it only partially makes up for the mountain of bad calls against us. This is of course, confirmation bias in action. 

We support policy because of liberal guilt, virtue signaling (on the right and left), the desire to be seen as tough, or good, or kind, or the desire to respond to negative aspects of our parent's world view, or "our brother who makes better money, but at least I'm not from the evil political party like he is". Its just all emotion self delusion, posturing, political laziness and issue crossover, childish temper tantrums, and emotional apes patting themselves on their back, unless your using logic to promoting the outcome of a cost-benefit analysis. 

The fact that we don't have dispassionate policy analysis is the greatest failure of the modern era. 

Examining the interest and motivation of each side, and evaluating the validity of these motivations is the only path forward.