Americans who oppose the policies of President Donald Trump plan to make their objections known on 15 March 2017 by flooding the White House with postcards in an event dubbed the “Ides of Trump” by organizers, who say they hope to see delivery of a million or more cards expressing disapproval of Trump and his agenda to 1600 Pennsylvania Avenue in the days following.

The name is a twist on the expression “Ides of March,” which most people probably know from its use in the Shakespeare play The Tragedy of Julius Caesar, in which a soothsayer ominously warns the doomed title character to “beware the Ides of March” (although to the Romans the phrase only meant “the 15th of March”).

An official Facebook page sets out the rationale and guidelines for the event:

There is also an Ides of Trump web site with a bare-bones FAQ and a list of postcard writing parties scheduled for cities across the U.S., but for the most part the campaign has grown organically, via Facebook and Twitter, and come together in little more than a month.

The Ides of Trump was the brainchild of two Californians, Zack Kushner of Berkeley and Ted Sullivan of Los Angeles, who it was inspired by the Women’s March and has received a of interest, not just from Americans but from Netizens all over the world. “To be honest, we have no idea the number of people participating,” Sullivan said via e-mail. “This is a true grassroots movement.”

When asked what message they’re trying to send to Trump, Sullivan boiled it down to a four-word phrase: “The one message we’d hope to get across to him is ‘not on our watch.’

“One of our key goals is to get under his incredibly thin skin,” he continued. “To keep the press focused on the real story. And, ideally, to get Congress to do their job and investigate Trump, his finances and his connections to foreign business interests.”

Grassroots politics works both ways, of course, so it came as no surprise to Sullivan and Kushner when a counter-protest was organized to flood the Trump White House with messages of approval and encouragement:

“It’s a free country and people are free to do whatever they want,” says Sullivan of the competing protesters. “If they want to send postcards to support the President, then do it. To be honest, it’s flattering to think our movement caught the attention of the opposition enough to warrant a response.”