Richard L. Hasen, an expert on campaign finance at the University of California at Irvine, recently wrote an article for Slate titled, “The Numbers Don’t Lie,” in which he showed that total outside spending, as measured through March 8 of every election season, seemed to explode after the Citizens United decision, reaching about $15.9 million in 2010 (compared with $1.8 million in the previous midterm cycle) and $88 million this year (compared with $37.5 million at the same point in 2008). “If this was not caused by Citizens United,” he wrote, “we have a mighty big coincidence on our hands.”

But there are alternate ways to interpret this data. The level of outside money increased 164 percent from 2004 to 2008. Then it rose 135 percent from 2008 to 2012. In other words, while the sheer amount of dollars seems considerably more ominous after Citizens United, the percentage of change from one presidential election to the next has remained pretty consistent since the passage of McCain-Feingold. And this suggests that the rising amount of outside money was probably bound to reach ever more staggering levels with or without Citizens United. The unintended consequence of McCain-Feingold was to begin a gradual migration of political might from inside the party structure to outside it.

And in his examination of raw numbers, Hasen managed to ignore what is probably the most relevant bit of data during this period: 2010 and 2012 were the first election cycles since the enactment of McCain-Feingold in which a Democrat occupied the White House. Rich conservatives weren’t inspired to invest their fortunes in 2004, when Bush ran for the second time while waging an unpopular war, or in 2008, when they were forced to endure the nomination of McCain. But now there’s a president and a legislative agenda they bitterly despise (much as Soros and his friends saw the Bush presidency as an existential threat to the country), so it’s not surprising that outside spending by Republicans in 2010 and 2012 would dwarf everything that came before. What we are seeing — what we almost certainly would have seen even without the court’s ruling in Citizens United — is the full force of conservative wealth in America, mobilized by a common enemy for the first time since the fall of party monopolies.

A consequence of McCain-Feingold has been to flip on its head an old truism of politics, which is that incumbency comes with a fixed financial advantage. In the era of soft money, controlling the White House meant that a party could almost always leverage its considerable resources to dominate fund-raising. But today it’s much easier to tap into the fury and anxiety of out-of-power millionaires than it is to amass contributions in defense of the status quo. This dynamic probably explains why wealthy Democrats who pioneered the idea of outside money during the Bush years have largely stood down this year, even while conservative fund-raising has soared. It isn’t that liberals don’t like Obama or grow queasy at the mention of super PACs. It’s a function of human nature: nobody really gets pumped up to write a $10 million check just to keep things more or less as they are.

If you’re a Democrat, there’s some good news here. One persistent fear you hear from liberals is that Citizens United altered the balance between the parties in a permanent way — that corporate money will give Republicans a structural advantage that can never be overcome. What’s more likely is that the boom in outside money will prove to be cyclical, with the momentum swinging toward whoever feels shut out and persecuted at the moment. Liberals dominated outside spending in 2004 and 2006. And should Romney become president, they’ll most likely do so again.

It’s worth asking just how much an advantage all of this outside money actually confers. The greatest impact of this year’s imbalance in outside money will be felt on the state level, where a lot of House seats and control of the Senate hang in the balance, and where a sharp gust of advertising can often blow the results in one direction or another. But a presidential campaign is different, focusing as it does on a dozen or so pivotal states and a limited number of advertising markets. There’s probably a limit to how many 30-second spots all of these groups can cram onto cable stations during late-night showings of “Turner & Hooch.”

I recently called Carter Eskew, a longtime Democratic adman and strategist whose clients included Al Gore in 2000, and asked him a simple question: How much did he think he would really need for a candidate today, if he could have an unlimited budget to run a national ad campaign, including all the outside money? Eskew paused before giving a declarative answer: $500 million. Anything beyond that, he said, was probably overkill.