Ah good old 3A, you know when I accidentally opened a paper for 3b I thought to myself; what drugs were my teachers taking so I could make sure my kids never went near it. I did the same when I saw 4b, the b options are far more interesting and better as a whole, but anyway someone has to pay the price for another's misuse of substances and those someone's would be us.
I write this intro as I procrastinate my overdue 3A essay. If you know what the question is asking for then I guess this needs no explaining…
The American political system is a two party system, although 3rd parties do exist they rarely grasp to power. Most Americans easily identify with one of the two major political parties, Republican or Democrat. The idea of having a president from one party and the majority of congress from another may not have been something the founding fathers had in mind when trying to create a functioning government, however, due to factors such as partisan de-alignment people no longer strongly identify with one party and seek to put their trust in a candidate that promises what they're looking for. For example, they may choose a democrat presidential candidate offering tighter gun laws and a local republican congressman candidate offering lower taxes, the voter may be aiming to gain the best of both worlds from a split ticket but may unconsciously be hindering the prospect of both reforms.