No military action led to the start of WW1; the catalyst to WW1 was the assassination of Franz Ferdinand, the archduke of Austria-Hungary. His murder by Gavrilo Princip – a Serbian nationalist, caused Austria-Hungary to declare war on Serbia, which drew the other European countries into the war due to their existing treaties of mutual defense.
Wilson wanted to created lasting peace across nations, so aimed for the creation of the League of Nations(later known as UN). The United States never joined it, and many people didn't want the country getting involved in foreign affairs
The existence of single-member districts discourages the creation of minor parties because the party that receives the most votes secures the office. In other words, the winner gets everything, and other parties have nothing to show for their efforts. If, by way of illustration, the Green Party fielded candidates in all 435 House races and received 20 percent of the vote in each district, it would not win any seats at all. In a system with proportional representation, seats in the legislature are allocated according to the party's share of the popular vote. Thus, minor parties are rewarded for fielding candidates in elections because their efforts result in at least a modicum of representation in the legislative branch.
