We should probably be relieved that the president of the United States denounced racism and white supremacy Monday.

But it’s hard to feel any reassurance after the mass shooting in El Paso, Texas, last weekend, which, according to a document published by the suspected shooter, belongs in a category of racially motivated mass murders like the ones at mosques in Christchurch, New Zealand, at the Tree of Life synagogue in Pittsburgh or at the Emmanuel AME Church in Charleston, South Carolina. (The motive of Sunday’s shooting in Dayton, Ohio, is not yet known.)

Each of these massacres can be dismissed as isolated incidents, the product of people with tortured minds, acting alone for reasons only they fully understand. But it should be clear by now that there is something much more sinister going on – an international movement built on a belief that the “white race” is facing annihilation as a result of nonwhite population growth and immigration, a theory known by various names including “White Genocide” and “The Great Replacement.”

According to research by Kathleen Belew, a professor of history at the University of Chicago and author of “Bring the War Home: The White Power Movement and Paramilitary America,” these shooters share more than a motive. There is also a shared strategy to combat this imagined threat: provoking a race war through lone wolf attacks.

A number of commenters have rightly pointed out how closely the shooters’ white power ideology matches President Trump’s rhetoric, as well as the ideas espoused by other American politicians, including some prominent Republicans in Maine. Perhaps out of embarrassment, the president went on camera Monday and decried racism and white supremacy. But we can’t expect that denouncement to do that much to stop the violence.

Donald Trump didn’t invent racism in America – he just takes advantage of it. When he talks about an invasion of immigrants or the need to ban Muslims from entering the country, or tells non-white members of Congress to go back to the countries they came from, he is playing on the same fears that drive the lone wolves.

And he’s not the only politician to push those buttons. When a few hundred asylum seeking families arrived in Portland this summer, Waterville Mayor Nick Isgro, vice chairman of the state Republican Party, published a video manifesto claiming that these immigrants were “human pawns in a game played by global elites” and warned that they were here to dilute the political power of long-time residents.

Former Republican U.S. Rep. Bruce Poliquin chimed in with a social media post Sunday, after the motive for the El Paso shooting was known. Poliquin announced he would not run for his old seat, expressing disappointment that he would not be there to “stop the invasion of illegals (sic) aliens.” The man likely to take his place on the ballot, former Republican state Sen. Eric Brakey, has tweeted about a socialist plot of “mass importation of new voters to transform our political culture.”

Just saying these things doesn’t make these politicians part of a terrorist movement, but it certainly makes life easier for those who are. Dehumanizing rhetoric – describing human beings as “pawns,” or “illegals” who don’t move unless there’s an “invasion” or they’ve been “imported” – reaches a much bigger audience when it is amplified by mainstream politicians.

Even with his strong words Monday, Trump continues to promote racist policies, including caging asylum-seeking families, shutting the door on refugees and declaring that we need to build a wall to protect ourselves from an alien invasion. Axios reported last month that race-baiting will be a central part of Trump’s 2020 re-election strategy.

It’s not enough to denounce mass murder after there’s been a massacre. Every single public official should be prepared to denounce racist delusions and racist policies every single day.