There are Three war goals for justification available in the menu: However, the formula behind this is unknown. It will take longer to justify on countries that are ranked higher and are farther away than you. Once you justify on an opponent, they will receive a notification that you justified on them. Justifications do not cost political power. This will bring you directly to the diplomacy screen. To go to your target's diplomacy menu click any of your target's city and then click on the flag in the city menu. You can do this by click Justify war on the targeted nation's screen in the diplomacy menu. It also is dependent on your capitals distance from the enemy. To declare a war, you have to give a Casus Belli (Latin for a cause for war) or war goal first, and it will take variable amounts of time depending on your ideology. The gameplay in Rise of Nations revolves around warfare, and declaring war is the base mechanic which diplomacy is built on.