Don't I have a right to buy a $10 yard sign? A $100 bard sign? A $1000 billboard? A $10K radio ad? A $50K book printing?
Why should I lose any of these rights because I join with others to help me afford it?
Makes me wonder if LLM's are going to be granted citizenship by this court.
And then, individual transistors.
Besides your premise is flawed to begin with, you most certainly cannot freely rent out a billboard and put anything you want on there, or a radio ad, or a book printing. Restrictions on content already exist, and I see no reason why an exception should be made for political parties.
As the heir apparent of the republican party, Jeb Bush raised a half-billion dollars from donors. He was politically connected, with a history of winning elections. His significantly outspent the other candidates -- and still lost. This isn't especially uncommon, money's influence alone doesn't determine elections.
There isn't a chance in hell with the current system that anyone who doesn't come from a wealthy background, or at the very least has the backing of a rich sponsor, would make it anywhere near the top of the list, which is the entire issue.
What would be most democratic is if tax money funded campaigns. Every candidate gets the same amount for that office. Take money out of the equation. It should not be a reason someone gets elected. That's corrupting and makes candidates beholden to monied interests.
The 1st amendment freedom of the press is by nature disproportionate!
Most citizens do not own a printing press. Most presses aren't upstream of a national distribution network. Not all twitter accounts have millions of followers. "Evenness of influence" is not constitutionally guaranteed or even a natural outcome, even in a democracy.
The 1st amendment doesn't guarantee you access to the most power communications equipment and audience, only that that the Government won't suppress what you manage to obtain.