If you're a candidate spouting conspiracy theories from the stump after the first presidential debate, the odds are you didn't win. That's what Donald Trump did Thursday when he offered—from prepared remarks, no less—the claim that Google is manipulating search results to suppress bad news about Hillary Clinton.

He made this claim without offering the slightest evidence. Google denied it, just as it did in June when the rumor first appeared as clickbait on a viral video site. (A pro-Trump Russian news site promoted the story more recently). Outside experts long ago debunked the bogus allegation, and showed that the site itself manipulated the search results to con people into concluding that Google was biased against Trump. But what if, for the sake of argument, Google were biased?

Google is not a public utility, though its service has become so essential to daily life that many people treat search as a basic resource, like water or electricity. Google is instead a public company with a legal obligation to act in its own self-interest. One way Google does this is through heavy political lobbying. It has a vested interest in who occupies the White House, and its employees are among the most generous supporters of the Clinton campaign.

"Google has every reason to expect more favorable treatment from Clinton than from Trump," says Benjamin Edelman, a Harvard Business School professor whose research has found bias in Google search results toward Google's own services. It's this alleged bias that has made Google the target of a massive European Union antitrust investigation. The Federal Trade Commission under President Obama declined to pursue similar action against Google, a decision he sees as leniency likely to continue under a Clinton administration. "The temptation to push consumers toward Clinton must be, at the very least, difficult to resist."

As a for-profit company, Google also possesses trade secrets. Google's most jealously guarded secrets are its search algorithms, from which the company generates most of its profits. The public in the end does not know how Google decides to surface the search results you see. Google could in theory build political bias (or any other kind of bias) into its search algorithms without users ever knowing. Not that Google is doing so. But its search engine is a black box. Users who hope and believe Google is providing neutral, unbiased results must ultimately take on trust that the company shares those values.

"We should all fear the world in which Google subtly pushes us toward the candidate it favors, without us even noticing, and without any serious prospect that competition from other search engines could restore balance," says Edelman, who describes himself as a Clinton supporter.

Platforms like Google and Facebook contain the seeds of their users’ own distrust in them—seeds that the Trumps of the world are all too happy to water with baseless claims.

The thing is, Google search isn't neutral. Like any other set of complex algorithms, search is shot through with the values of its creators. Take, for instance, Google's own response to Trump's conspiracy theory claim of pro-Clinton bias. "Our autocomplete algorithm will not show a predicted query that is offensive or disparaging when displayed in conjunction with a person's name," a Google spokeswoman told CNN. In building an algorithm that won't suggest offensive searches connected to people's names, Google is making an editorial decision about the search results it publishes, much as Facebook inscribes its own editorial values into which news stories are prioritized in users' News Feeds. These platforms can never be truly neutral, since engineering a system to display one thing necessarily means something else remains hidden. Those choices may not represent political biases, but they are biases toward one value over another—civility versus abuse, say, or serious news versus tabloid trash. As any journalist knows, pure objectivity is a fiction.

And like journalists, Google has a right to an editorial point of view. The First Amendment would seem to allow Google to favor one candidate over the other in search results if it wanted to, at least so long as it didn't claim it wasn't favoring one over another. But that's not the role with which users have entrusted Google. It is supposed to be neutral, pure, a medium without a message. The problem is that platforms like Google and Facebook contain the seeds of their users' own distrust in them—seeds that the Trumps of the world are all too happy to water with baseless claims. So long as Google search remains a black box, conspiracy theorists will say something nefarious is happening within that box. Trump, on the other hand, doesn't have an opacity problem. His lies are quite transparent.