Lots of people want to interfere in the upcoming U.S. presidential election — including Americans. Because there is little authorities can do to restrain misinformation-mongers here at home, the campaigns and candidates themselves are our best hope.

Domestic actors on both sides of the aisle have been experimenting with social media manipulation ever since Russia taught them how well those tactics can work — from misleading “news” stories to fake Facebook events to trolls stomping around Twitter. These misrepresentations would be troubling in any environment. In an age of warfare over what is real, they are downright dangerous. But, while the government can act against foreign incursions, the First Amendment prevents most attempts to clamp down on information operations carried out by citizens.

Political candidates, by and large, have a right to lie, and they have a right to buy up a bunch of bots to pollute platforms with propaganda without voters knowing the difference (except perhaps in California, which as of July 1 has a “bot law” of its own). They just have to choose not to.

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 Donald Trump’s re-election 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 Trump’s re-election 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.

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 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 Biden has pledged to also avoid other tricks as well. His rivals should follow, and fast.

FROM AN EDITORIAL IN THE WASHINGTON POST