If you judge return on Super PAC investment by candidates elected, then the massive spending by conservative outside groups was a failure. Despite spending more than $100 million, only a handful of candidates backed by Karl Rove’s American Crossroads, for example, won a victory on Tuesday. Likewise, Sheldon Adelson invested $57 million of his money into congressional elections — to little avail—and the collected Romney super PACs failed to deliver the election to their candidate. Millions were spent to boost Republican Senate candidates and break the Democratic majority, to no avail — in 2013, Democrats will have a larger and more liberal majority in the Senate

This fact has led observers to conclude that super PACs have been a bust. David Weigel, for example, wrote that we might be making the “wrong assumption about big donors. Maybe they have no idea how to spend their money effectively.”

But that relies on a fairly narrow definition of “effective.” If you expand it to include “electoral influence,” it’s not at all clear that spending was wasted. For starters, the mere act of spending tens (or hundreds) of millions of dollars on an election has an effect on the policy views of the candidates the groups are trying to elect, and the issues they’re discussing. For example, the New Republic’s Alec MacGillis has noted that Mitt Romney’s pivot to the center — his “Etch A Sketch” moment — was delayed by the fact that he had to raise money from GOP mega donors who wanted him to commit to hardline conservative positions. A world where Romney won is one where there would have been a huge return on investment in policy terms; just because their favored candidates lost doesn’t mean that it wasn’t a worthwhile way to spend money.

There’s also the question of broader influence on the political system itself. Potential candidates at every level of government — across the political spectrum — now know that there are people willing to invest millions to either help them, or defeat them. Indeed, the mere possibility that Super PACs may spend big in elections will change the landscape of American politics — who runs, how they run, and what they run on — in ways that are, at the moment, subtle and hard to predict.

Finally, if we are going to use the crudest estimation of success — votes won — it’s not even clear that mega donors were unsuccessful! Because there’s no way to hold a control election where Romney ran without super PAC money, it’s impossible to say what would have happened without massive spending from Republican donors. It’s possible — and I’d say, likely — that super PAC spending added a percentage point or two to Romney’s final total. Given the high stakes of a presidential election — and the small margins separating Obama and Romney — this is money well spent, and provides a useful starting point for the next cycle.