Imagine you and I at a negotiating table. We are attempting to solve a border crisis between our countries. It doesn't matter which side did what. Drizzistan wants a particular outcome and Randomstan wants a particular outcome. The basis for diplomacy is compromise and concession, meaning that in order for diplomatic solutions to actually be effective, each side must benefit or there must at least be the appearance of benefit. Regardless of Randomstan's actions, your country refuses to budge on the critical central issue. It's out of the question to negotiate that away and it is Randomstan's right to take such a stance.

However, resolving that issue is critical because Drizzistan views it as crucial to it's interests. Drizzistan cannot accept Randomstan's refusal to budge on the matter. So negotiations continue on, chipping away at the edges of the debate and scoring cosmetic and political points for both sides...but the primary issue can't be resolved because neither side can accept a defeat on it. So what happens from there? There are many legitimate reasons and things to not negotiate away in the face of diplomacy...but sometimes that diplomacy cannot function without those concessions.

Eventually, things will get to the point where diplomacy breaks down and if the issue is important enough, peaceful means of solving the problem are replaced the forceful means. This isn't a commentary on pro-war/anti-war. This is a deeper point: successful diplomacy requires you and others to sell out your principles in order to achieve peaceful conflict resolution. And when one side sees an issue as non-negotiable and the other side sees it as a vital compromise...what then?

Peaceful means are the most desirable in all circumstances. But given human nature, people are born and grow up with differing levels of tolerance towards voluntary peaceful discussion and have different attitudes, different goals, and different philosophies. This is reality and the only way to change it would be a global eugenics/re-education campaign that is completely unfeasible, immoral, and would inevitably lead to active opposition. Since humans will always be plagued by tyrants, murderers, and thieves and since these kinds of people show the most apathy towards peaceful conflict resolution, there comes a time when force must be used. We are well aware of the breadth of people who refuse to listen to reason. If you can't get someone to cut a deal with you and you can't convince them of the stupidty of their stance and choices...if the issue is serious enough, there is no other option but force.