Much ink has been spilled over the horrible effects of the Supreme Court ruling in Citizens United v. Federal Elections Commission, but relatively few Americans realize that judicial activism against campaign finance law began much earlier. Opposition to misguided court doctrine also began decades ago, although it is only recently reaching a national tipping point.

While it's true that the Citizens United ruling further opened the floodgates to big money in politics, that money was already flowing. The fact is, sensible rules to stem the influence of billionaires and powerful interests have been hampered by a ruling that is much older, Buckley v. Valeo, which came on Jan. 30, 1976.

In Buckley, the Supreme Court struck down much of the post-Watergate laws aimed at preventing another scandal that was big enough to take down a sitting president. These days, such scandals feel routine. The court struck down a policy that set an equal amount that each candidate for Congress could not exceed, as well as limits on how much any wealthy candidate could spend. The result has been to greatly advantage personally wealthy candidates such as former New York City Mayor Michael Bloomberg, former New Jersey Gov. John Corzine and Donald Trump.

But the most damaging aspect of the Buckley ruling was to reject the common-sense notion that in order for all voices to be heard in a policy debate, we must limit the amount that each individual can speak. We apply limits on the amount of speech anyone has in public comment period at a city council meeting or on the floor of Congress. But while spending money is hardly the same thing as actually speaking with your own voice, the court has refused to allow limits on the amount that billionaires can spend on political advertisements.

Contrary to today's polarization of both the Congress and the Supreme Court, the Buckley ruling was bipartisan and so was opposition to it. While no justice was willing to put their name on such an intellectually flimsy decision, Buckley is widely believed to have been written by liberal Justice William Brennan, pro-corporate Justice Lewis Powell and centrist Justice Potter Stewart. Opposition to the ruling mounted in the U.S. Senate, with five Republican senators joining 48 Democrats voting to support a constitutional amendment to authorize limits on campaign spending in 1988 – 12 years before Citizens United.

It takes decades to reverse misguided court rulings, but what is instructive about the history of Buckley v. Valeo is just how far the movement to overturn it has come in the past 40 years. The idea has gone from obscurity, to ridicule, to the point where it is now a central pillar of both Bernie Sanders' and Hillary Clinton's presidential campaigns.

Through an arduous, decades-long process of public discourse, we have elevated an obscure court ruling into a national consensus, with more than three-quarters of Americans agreeing that there should be limits on political spending. With public opinion that broad, spanning all political parties, it is only a matter of time before the Buckley ruling falls. The question is, how?

It is possible (although not certain) that changes in court personnel will allow the Supreme Court itself to reverse Buckley more quickly than citizens can overturn it with a constitutional amendment. But even if that happens, we would be wise to continue the push for an amendment until it is ratified, lest the composition of the court change yet again in 10 or 20 years. Allowing five unelected judges to dramatically change the fundamental rules about how we conduct campaigns every few decades based upon their own whims is no way to take self-government, or our Constitution, seriously.

Further, it is likely that a future court might take only small steps to chip away at previous court doctrine, rather than undermine the court's own credibility by continuing to flip-flop dramatically and ignore its own precedents. We could easily see a future court walk things back to where they were before the Citizens United ruling, but leave in place the flawed logic of Buckley.

Finally, one also has to wonder whether the drafting process of one judge writing an opinion, perhaps with the aid of a few junior clerks, would yield a better product than a constitutional amendment that would be publicly debated in congressional committees and offer opportunities for input from the best constitutional scholars across the country.