Every day, Americans see hundreds of ads on TV and radio, in newspapers and magazines, on billboards and smartphones. North Americans post to Facebook something like a billion times a day, and during the election many of those messages were about politics. Facebook typically runs about $40 million worth of advertising a day in North America.

Then consider the scale of American presidential elections.

Hillary Clinton’s total campaign budget, including associated committees, was $1.4 billion. Mr. Trump and his allies had about $1 billion. Even a full $100,000 of Russian ads would have erased just 0.025% of Hillary’s financial advantage. In the last week of the campaign alone, Mrs. Clinton’s super PAC dumped $6 million in ads into Florida, Pennsylvania and Wisconsin.