What distinguishes independent expenditures in political campaigns?

Independent expenditures are characterized by being made without coordination with any candidate's campaign. This means that individuals or organizations can spend money on political advertising or other campaign-related activities without being directly linked to or influenced by a candidate's strategies or messaging. This distinction is crucial as it allows for more robust spending and an increase in the influence of external entities in elections, thereby impacting the political landscape.

The aspect of independence from the candidate's campaign is significant because it alters how campaign finance operates. Without the need for coordination, entities can express their support or opposition to candidates in ways that align with their separate interests, leading to greater diversity of viewpoints and messages in the campaign.

While there are legal limits on contributions and donations to candidates (which relates to why option B is incorrect), independent expenditures themselves do not face the same constraints as long as they are not coordinated with the candidate's campaign. The idea that independent expenditures must be coordinated is fundamentally contradictory to their definition, ruling out option A. Finally, independent expenditures apply broadly, not just to third-party candidates but also to major party candidates, making option D inaccurate.