It’s said that villagers in remote parts of China take stones from dilapidated sections of the Great Wall to build their homes. From the villagers’ perspective, at least the stones are being put to good use, given that the wall long ago ceased being effective at keeping out invaders. Not much more useful, these days, is the edifice Congress built after the Watergate scandal to limit the influence of money in elections. Our current campaign finance regime, after years of Supreme Court decisions like Citizens United, which freed up corporations and unions to spend unlimited sums and gave rise to super PACs, is remarkable mainly for how little spending it stops. In January, the Federal Election Commission estimated that $7 billion was spent by candidates, parties, and outside groups in the 2012 elections. That’s an order of magnitude more than what was believed to be spent in the 1972 elections, which originally inspired Congress to enact systemic campaign finance laws. And on Tuesday, the Supreme Court agreed to hear a case that offers the justices another chance to haul off with a few more stones. The case has the official name of McCutcheon v. Federal Election Commission but some people are already referring to it as “Citizens United II.” The issue is the constitutionality of federal law that caps the total amount of money individuals may contribute to candidates, parties, and certain political committees over a two-year period. Shaun McCutcheon, an active political contributor to the GOP and its candidates, challenged the caps, which are currently set at $117,000, as a violation of the First Amendment’s guarantee of freedom of speech.