So a reason is valid because you say it is? Come on, give me a validated list with a source, if one exists, otherwise simply admit that people start wars and make the reasons up if they need to.ALEXIS_DH said:to complete your quote in bold.
.....the mysterious sinking of the USS Maine ship which led the US to blame the Spanish and start the Spanish-American War. Some critics have claimed that the sinking was intentional [1].
casus belli is not an excuse a country puts up, that is "valid" just because the country says so.
there is a legal framework around it. you cant say, for example, a brazilian timberer in peru grants peru the defensive position if it started a war. (for the claim to be valid, there should be a customary practice or a legal precedent) you also say
i dont define the terms of makes you an agressor. thats defined by casus belli. and the definition of what is "valid" casus belli is for the most part customary. it is rooted on precedents. (thats the customary part on customary international law). you just cant say "the first one to find a excuse", because its not about an excuse, but of what constitutes a valid act of war against one (valid being what is widely and customarily accepted as valid), and reason enough to retaliate in self defense. its not rationalized backwards. for the most part most "reasons to go to war" are already established. you just cant go and make up a new one to fit your needs.
and unless is some extremely rare action, never seen before (so that there is no precedent)... you cant retroactively find an excuse. casus belli is full or precedents, its definition is already shaped by them (and the lack of precedents in spite of widely known action).
so its not like X happens and you say "hey this is casus belli" (unless you are talking something so very extraordinary that there is no precedent).
now, back to 1967. you have (besides the mounting of troops on the borders, which for its own sake can be argued as a reason to go to war) the blockade of the tiran strait. that is customarily accepted as an act of war. do you want me to dig for a case??? or is it intuitively reasonable why a naval blockade is an act of war??
http://en.wikipedia.org/wiki/Blockade
now, you ask me "Care to provide a list of valid reasons to go to war?"
i know a few..., blockades, bombarding, infantry invasion, magnicide (or whatever its spelled when you kill a president or a king), formal war declaration.... yet that list is not conclusive. there are many more reasons.....
i believe those 5 i just said are pretty intuitive and self-explaining.. and 48, 67 and 73 casus belli fall under those or other intuitive casus belli and there is no need to dig for a relevant case to back up.
Edit: BTW, infantry invasion is an act of war, not a reason to declare war and a declaration of war is an act of war also.