I considered moderating this down, but I will reply instead. This is such a warped, confused view of history it's hard to know where to start. However; there is such a thing as a just war, international security is hard, and Russia had and has no right to Crimea or the Ukraine. Iraq WMDs: I remind you that Saddam believed he had WMDs. As for the Lusitania, I would remind you Churchill had his hands full with a minor issue called Gallipoli. And in Syria and Libya, there were no good options, and the situation was not of the West's making; it's difficult to know when a market trader's messy suicide will start a regional revolution.
We are lied into every war; every single one. The actual reasons we go to war often have to do with economic or strategic interests. But people don't get ready to fight and die for economic interests. They fight and die for survival. So you make it about survival, and tell the people how the enemy is coming to kill their children in their beds. Or you appeal to their sense of righteousness and tell them how we must save this other poor downtrodden people from the dictator we installed (oops, did I say that last part out loud?). After all, it is the leaders of the country who determine the policy. The people can always be brought to the bidding of the leaders. That is easy. All you have to do is tell them they are being attacked and denounce the pacifists for lack of patriotism and exposing the country to danger. The United States isn't the only place this is done, of course. It works the same way in any country.