What a number of observers have noted about the Citizens United or Hillary the Movie case is true. The Supremes went out of their way to make it a constitutional case when they clearly had other options. They could have ruled narrowly without getting to the constitutional issue that e.g., the McCain-Feingold law didn't really cover movies distributed through On Demand. But they wanted to invalidate the law that prohibited corporations (profit and non-profit, including advocacy groups like NRA and ACLU) from saying anything that even smelled like electioneering 30 (primary) or 60 (general) days before an election. It was a healthy impulse. If the First Amendment means anything, it's protection of the freedom of political speech, no matter who says it or (considering technology) how, especially in the time around an election. McCain-Feingold is profoundly subversive of basic liberties. Theoretically elections are how we control the government, but if the government controls elections with minute rules, they (the permanent government) end up with zero accountability -- not that it has much in the best of circumstances, but as long as there's a shred of a constitution there's a ghost of a chance..
The fact that the Supremes stretched to reach this result -- generally uncharacteristic, they usually try to avoid constitutional issues unless absolutely necessary -- raises the question of whether they're moving into a more aggressive mode. As a barely conservative court with a clearly liberal administration, it's possible. As this Register editorial notes, the McDonald v. Chicago case, which tests whether the Second Amendment applies to state and local governments, will give us a pretty good hint.