The National Security Agency monitored German Chancellor Angela Merkel's cellphone for years, as well as the communications of other unidentified foreign leaders. That's prompted an intriguing if unsubstantiated question about the NSA's potential snooping on U.S. politicians: "Did Obama spy on Mitt Romney?" asks Alex Tabarrok at Marginal Revolution.

That question would have seemed straight out of the "right (or left) wing loony bin" even a few weeks ago, Tabarrok adds, but "today, the only loonies are those who think the question unreasonable." As Tabarrok sees it, the NSA almost certainly collected Romney's "emails, photos, texts, or other metadata" in its widespread data hoovering, and Romney, after all, probably spoke with Merkel on her bugged phone at some point.

Did the NSA use the information they gathered on Mitt Romney and other political candidates for political purposes? Probably not. Will the next president or the one after that be so virtuous so as to not use this kind of power? I have grave doubts. Men are not angels. The Nixon administration plumbers broke into the offices of Daniel Ellsberg's psychiatrist in order to gather information to discredit him. They busted into a single file cabinet.... What a bunch of amateurs. [Marginal Revolution]

So, what's to keep the NSA from spying on politicians for their own political gain or that of the president? Well, for starters, the law.

Even with the newly disclosed surveillance powers granted to or seized by the NSA, the agency isn't allowed to legally snoop on Americans residing in the U.S. That doesn't mean there aren't abuses, but the worst domestic violation uncovered so far is the NSA staffers snooping on their girlfriends — a practice cleverly dubbed LOVEINT.

Unlike, for example, Brazil's main intelligence agency, there's no evidence the NSA has actively eavesdropped on members of Congress or Supreme Court justices. The Catholic cardinals gathered to elect the next pope? Maybe. But the NSA's job is to monitor foreign signal intelligence (SIGINT).

There are lots of legitimate concerns about the NSA's indiscriminate collection of Americans' email and phone metadata, national security journalist Joshua Foust tells Business Insider. But even Glenn Greenwald, the NSA critic and former Guardian journalist who broke many of the stories from NSA leaker Edward Snowden, hasn't published any proof of NSA abuses, Foust says. "He's had those documents for months, where is the evidence? Evidence of capability is not evidence of abuse."

Still, the Snowden case is one of the big red flags waving at the NSA, says Conor Friedersdorf at The Atlantic. The relatively low-level contractor was able to break the rules and pilfer reams of sensitive documents. "It isn't hard to imagine an alternative world in which the man in Edward Snowden's position was bent not on reforming the NSA, but on thwarting its reformers — that he was willing to break the law in service of the surveillance state, fully believing that he was acting in the best interests of the American people."

This Bizarro Edward Snowden wouldn't have to abscond to a foreign country with thousands of highly sensitive documents. He wouldn't have to risk his freedom. Affecting a U.S. presidential election would be as easy as quietly querying Rand Paul, or Ron Wyden, or one of their close associates, finding some piece of damaging information, figuring out how someone outside the surveillance state could plausibly happen upon that information, and then passing it off anonymously or with a pseudonym to Politico, or The New York Times, or Molly Ball. Raise your hand if you think that Snowden could've pulled that off. [The Atlantic]

Friedersdorf lays out some other scenarios in which the NSA's chief, a rogue employee, or even "another Richard Nixon type in the Oval Office" could abuse the power of the spy agency to destroy an unfriendly candidate. Romney wasn't spied on, "because I doubt Obama would have dared order it; and because neither the NSA nor a contractor like Booz Allen Hamilton nor the national security state generally was threatened by a Romney victory," he adds, but why risk it by allowing such a powerful surveillance state? He proposes this governing principle:

If a powerful institutional actor within government has a strong incentive to do something bad, the means to do it, and a high likelihood of being able to do it without getting caught, it will be done eventually.

"My preference would be that the NSA not cast so broad a net," agrees Dave Schuler at The Glittering Eye. "In the absence of any real evidence" that the NSA is trying to influence U.S. elections, it looks like "Tabarrok's fears are overblown." But "if any U. S. administration exploits the vast amount of information we're gathering for domestic political purposes the president whose administration it is should be removed from office whether he or she knew about it or not."