Another American synagogue has been attacked — with deadly results. A gunman opened fire in a house of worship on Saturday in Poway, California, killing one person and injuring three others. It's long past time we ask: What are authorities going to do about the deadly surge of anti-Semitism in the United States?

There's no question we're experiencing such a surge. It's been apparent since the 2016 presidential campaign, when journalists were swamped on Twitter with anti-Jewish slurs and memes containing Holocaust imagery. The marchers in Charlottesville famously chanted that "Jews will not replace us." Now, Saturday's deadly attack — coming six months after the massacre at a Pittsburgh synagogue — should sufficiently prove that American racists have been radicalized to the point of violence.

The response of American leaders has been fairly flaccid to date. Yes, they've condemned the attacks, but many seem more interested in pinning responsibility on their political rivals. (Republicans, for example, blamed Rep. Ilhan Omar (D-Minn.) for Saturday's shooting, even though the alleged shooter's apparent manifesto seemed to indicate a white supremacist bent.)

What those leaders haven't really done is offer a plan to fight back.

This is desperately needed. The youngest victim of Saturday's attack was an 8-year-old girl, Noya Dahan, who was hit by bullet fragments during the shooting spree. "I never thought that was going to happen to me because like it's a safe place, you're supposed to feel safe," she told ABC News.

It's time to do better.

Fighting anti-Semitism in the United States isn't going to be easy. The ugly and irrational hatred of Jews is a phenomenon that has persisted through the centuries and across national lines. But there are some efforts that can be made to mitigate its impact.

First, federal officials can renew their efforts to monitor and investigate domestic terrorism. Saturday's attack came just a few weeks after reports emerged that the Department of Homeland Security had disbanded its group of analysts who focused on stopping such attacks. That occurred even though domestic terrorism is arguably one of the biggest threats to American national security: In 2017, 150 Americans were arrested for plotting attacks in the United States, compared to 110 arrests of international suspects.

That commitment requires action by the Trump administration — which seems uninterested in this growing threat. "Government can play a key role in preventing violent extremism. But we need resources and coordination to undermine extremism," George Selim, a former Homeland Security official, wrote recently. The problem? "DHS is not only failing to increase resources to deal with new threats, it is also eliminating both staffing and millions of dollars in grants and programmatic support," Selim wrote.

The Trump administration probably stands in the way of a second obvious path to combating extremists: cracking down on easy access to the types of guns that mass shooters favor. The shooter in Saturday's attack reportedly used an "AR-type assault weapon" — obviously intending a high body count. That news is depressingly familiar to anyone who has followed mass shootings in the United States in recent years: AR-15-style rifles were used in the massacres at Las Vegas, Parkland, Orlando, and Newtown.

That, however, is a relatively recent development: The Federal Assault Weapons Ban of 1994 outlawed the manufacture and civilian use of many automatic and semiautomatic weapons for a decade. During that time, researchers have determined, mass shootings were less likely to occur. Combating hateful extremists is difficult enough — it's more difficult when they're armed to the teeth. Proceeding on this front, however, will require changes of governance in the White House and Senate.

But there are ways to combat extremism that don't require the action of government or a change in political parties. Individuals and institutions everywhere should call out the wicked lie of anti-Semitism everywhere it appears. The persistence of anti-Semitism has depended upon falsehood after falsehood — untruths about the nature of power, untruths about the most horrific events of modern history, and untruths about the people who try to influence events even now.

Those lies become the foundations of violent attacks like the one in Poway.

Battling anti-Semitism effectively will have ripple effects. The alleged shooter at Poway is also suspected of arson at a nearby mosque in March. His purported manifesto contained "hateful statements against Jews, Muslims, African Americans, Hispanics, immigrants, and feminists." Hatred begets hatred, it seems.

So it's best to fight that hate on all fronts.

As writer Peter Beinart tweeted over the weekend: "If you foment hatred against Muslims don't offer your sympathy when hatred kills Jews. Anti-Semitism and Islamophobia are two symptoms of the same white nationalist disease. You either fight them both or you are complicit in them both."

What is clear after the shootings in Poway and Pittsburgh — as well as the mosque massacre in New Zealand and the Easter Sunday bombings in Sri Lanka — is that combating such violent extremism can no longer be deferred. The time is now.