Why did isolationist ideas become even stronger in the united states in the 1930's ?

According to the video, what are the potential negative effects of pacs? check all that apply. billions of dollars can be spent on a single election. wealthy supporters can determine who wins an election. voters have no opportunity to see unbiased ads or posters. candidates without rich backers have no chance of winning. pacs have the power to damage a campaign beyond repair. candidates are not allowed to run without the support of pacs.