Research I have been directing in recent years suggests that Google, Inc., has amassed far more power to control elections—indeed, to control a wide variety of opinions and beliefs—than any company in history has ever had. Google’s search algorithm can easily shift the voting preferences of undecided voters by 20 percent or more—up to 80 percent in some demographic groups—with virtually no one knowing they are being manipulated, according to experiments I conducted recently with Ronald E. Robertson.

Given that many elections are won by small margins, this gives Google the power, right now, to flip upwards of 25 percent of the national elections worldwide. In the United States, half of our presidential elections have been won by margins under 7.6 percent, and the 2012 election was won by a margin of only 3.9 percent—well within Google’s control.

There are at least three very real scenarios whereby Google—perhaps even without its leaders’ knowledge—could shape or even decide the election next year. Whether or not Google executives see it this way, the employees who constantly adjust the search giant’s algorithms are manipulating people every minute of every day. The adjustments they make increasingly influence our thinking—including, it turns out, our voting preferences.