You should read the courts opinion on Citizens United. Essentially, the court said the political system is set up for money and its up to "we the people" to regulate the money. To restrict speech just so less money is thrown into a system we created and we support isn't constitutional.

If the decision would have give against Citizens United then speech could be restricted when it coincides with a political campaign. The case was about a company wanted to put out a movie that was critical of Hillary Clinton that came out near the 2012 primaries. They allowed the company to have the film because it is speech.

Just because the politicians WE elect and WE support who are supposed to represent US are more than happy to take millions doesn't mean speech should be restricted.

It's up to "we the people" to deal with billion dollar campaigns. The courts can't save us from our apathy and our ignorance. We can force our politicians to create legislation to restrict the billions in bribes and corruption but that takes an informed population. We are mostly ignorant and can't be bothered to read.

From Wikipedia: This ruling was frequently characterized as permitting corporations and unions to donate to political campaigns,[24] or as removing limits on how much a donor can contribute to a campaign.[25] However, these claims are incorrect, as the ruling did not affect the 1907 Tillman Act's ban on corporate campaign donations (as the Court noted explicitly in its decision[26]), nor the prohibition on foreign corporate donations to American campaigns,[27] nor did it concern campaign contribution limits.[28] The Citizens United decision did not disturb prohibitions on corporate contributions to candidates, and it did not address whether the government could regulate contributions to groups that make independent expenditures.[22] The Citizens United ruling did however remove the previous ban on corporations and organizations using their treasury funds for direct advocacy. These groups were freed to expressly endorse or call to vote for or against specific candidates, actions that were previously prohibited.