Having lost the popular vote, but winning the presidency with a margin of 77,744 votes in specific locations, it is not hard to imagine that Trump's success could have been thanks to carefully targeted political ads.
Of course it's impossible to say whether Trump would have won even if he hadn't spent any money on Facebook ads, but we're talking about a campaign that spent hundreds of millions of dollars in total. If this amount of money doesn't include enough to influence 78k people to go out and vote for a specific candidate, then we might as well give up on the very concept of advertising.
https://www.washingtonexaminer.com/weekly-standard/the-elect...
Of course it's impossible to say whether Trump would have won even if he hadn't spent any money on Facebook ads, but we're talking about a campaign that spent hundreds of millions of dollars in total. If this amount of money doesn't include enough to influence 78k people to go out and vote for a specific candidate, then we might as well give up on the very concept of advertising.