Not surprisingly, the president has been a leader in this realm — in the wrong direction. Routine retweeting of fraudulent accounts, along with promotion of distorted video, conspiracy theories and other manufactured narratives, is the least of it. Last month, the Associated Press reported on a series of social media ads for President Trump’s reelection featuring personalities such as “AJ from Texas,” a Hispanic man on a city street. But it turns out AJ is not from Texas, and his name is not AJ. All the president’s supposed supporters were models in stock footage produced overseas. Weeks earlier, the New York Times discovered that a consultant for Mr. Trump’s reelection campaign was publishing smear websites disguised as official pages for Democratic candidates. The most prominent displays GIFs of former vice president Joe Biden touching women and girls alongside blurbs about his opposition to court-ordered busing.
Mr. Trump may be a lost cause, but that doesn’t mean other Republican candidates in 2020 have to be, as well. Early attempts at a bipartisan arms-control treaty barring illicit campaign strategies between the two national congressional committees fizzled out late last summer. It could still be revived if leaders can muster the will.
Then there are the Democrats. The 50 state committees have passed a resolution asking for a partywide framework that would discourage candidates from copying Moscow, which the Democratic National Committee will soon have a chance to ratify. Perhaps most important, presidential contenders have an opportunity to lead exactly as Mr. Trump has not — by promoting the norms of an honest contest rather than eroding them. Most of these hopefuls forswore the use of hacked materials months ago, but only Mr. Biden has pledged to also avoid other tricks as well. His rivals should follow, and fast.