Casino billionaire Sheldon Adelson’s pockets are deep enough to make him a force in any election he might decide to get involved with. But by sweeping away a host of federal campaign-finance rules, the Supreme Court’s 2010 Citizens United ruling, along with related cases, gave Adelson unprecedented clout. He and his wife, according to the Center for Responsive Politics, have donated about $36.5 million just to conservative super PACs — about one-seventh of all the money raised by such groups. But that’s only part of the story. Many donations to independent political groups aren’t subject to disclosure. Adelson has given generously to such groups. And in an interview with Politico, he indicated he could fork over millions more before election day — bringing his total contributions, both disclosed and undisclosed, to as much as $100 million.

That makes him the most influential non-candidate in recent history — a modern counterpart to the Gilded Age robber barons who financed campaigns long before campaign-finance regulations sought to limit the amount any individual can spend to influence an election. Like the robber barons, Adelson has a policy agenda; his includes torpedoing the Israeli-Palestinian peace talks and having less scrutiny of his own company’s overseas operations. And just as critics said during the Gilded Age, Adelson’s level of influence is simply unfair. Not only does it distort the democratic process, but it undercuts a basic assumption of the Citizens United decision: that campaign expenditures that purport to be independent from political candidates and parties are, in fact, independent.

It’s now completely clear that donors see giving to nominally independent super PACs, many of which were created to support specific candidates, as tantamount to old-style campaign contributions. This becomes evident when Adelson tells Politico, “I gave 5 million or 10 million — I forget — to Newt Gingrich.” In fact, he donated to a super PAC that was supporting Gingrich.

After Gingrich quit the race, Adelson shifted his support to Mitt Romney and has become a force behind the scenes for tighter coordination among ostensibly independent super PACs. Adelson has used his donations, according to Politico, to discourage GOP-oriented political groups from acting out of concert with the others. The Romney campaign may not have full control over what outside super PACs do on its behalf, but neither are these organizations acting alone.

Earlier this year, the Supreme Court declined to reconsider Citizens United, but the mounting evidence that super PACs aren’t, in fact, independent might create new opportunities for legal action. Failing that, Congress can enact stronger disclosure measures and explore ways to limit coordination among parties, candidates, and supposedly independent donors.

Not only does Adelson’s influence distort the democratic process, but it undercuts a basic assumption of the Citizens United decision.

Meanwhile, the Dorchester-born Adelson controls an extensive casino empire with properties in Nevada, Pennsylvania, Macau, and Singapore. Its operations have come under scrutiny by the Justice Department and the Securities and Exchange Commission. In his interview with Politico, Adelson ascribed leaks of information about those cases to an effort by the Obama administration to discredit a major Republican donor. Right or wrong, his argument highlights a problem no one anticipated: When a donor becomes so big a part of either party’s fund-raising that any official scrutiny of his or her business interests can be dismissed as a political vendetta, it undercuts the ability of federal law enforcement agencies to do their jobs. Likewise, if Romney were to be elected and the Justice Department were to abandon its probe of Adelson, many Democrats would cry foul.

For his part, Adelson says he has nothing to hide, and has channeled most of his political giving through vehicles that require disclosure of donors. Still, at least $20 million has gone to groups that do not disclose donors. In other words, even a somewhat transparent political donor such as Adelson has given vastly more money to secretive political groups than average voters will ever see in their lifetimes. And no one will ever know how candidates are repaying their patrons’ generosity.