Andrew Jackson worried that annexing (aka adding) Texas to the US would divide the nation because Texas would enter the Union as a slave state. During the early to mid 19th century, US presidents were constantly trying to balance the number of free and slave states. Their reasoning behind this is that they did not want any side (aka free states or slave states) gaining too much power in Congress.
During this time, Northern politicians were worried that having a lot of slave states in Congress would result in the slave states making slavery legal in all of the new territories gained by the US during the 19th century. The Southern politicians were worried that if free states controlled Congress, they would try to make a law/amendment to get rid of slavery.
<span>The assassination of Archduke Franz Ferdinand in the Balkan city of Sarajevo provided the Austro-Hungarian government with a pretext for crushing Serbian nationalism, something it had long desired.</span>
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.
