If Israel was “caught off guard,” as the New York Times put it, by the threat posed by Iranian proxy terror groups, is America faring any better? That’s the question pressed today by the ex-speaker of the House, Kevin McCarthy. He warns that terrorists are exploiting our open borders. And in the starkest terms he warned against appeasement toward Iran. All this in a season when Iran’s proxy has taken root at Venezuela and Al Qaeda is resurgent in Afghanistan.

Mr. McCarthy’s remarks at the Capitol today come in the context of an unfolding appraisal in Israel of how the Jewish state, though renowned for its intelligence prowess, ignored danger signs in respect of the Islamic republic and its terrorist cat’s-paws. The attacks on the holy day of Simchat Torah staggered Israel’s leaders and citizens of all stripes, and for desperate hours Israel was fighting terrorists for control of towns and kibbutzim on its own territory.

Mr. McCarthy’s remarks are an important moment. That a disaster like this could befall Israel, whose survival as a nation depends on defending itself from hostile neighbors, puts a spotlight on our counter-terrorism efforts, launched in the aftermath of September 11. Yet the Biden administration is warming up to the sponsors of the terror attacks that day, the Taliban, by arguing that the militant Islamists can be trusted to fend off Al Qaeda in Afghanistan. 

“We cannot repeat what happened in Afghanistan,” Mr. McCarthy says, referring to the Biden administration’s bungling there. Yet Mr. Biden and his camarilla appear set on a course of engagement with the Taliban in lieu of “support for fighters who seek to free the country from the yoke of its oppressor,” our Benny Avni reports, even as the United Nations warns the country is now a “safe haven” for Al Qaeda. 

Mr. McCarthy’s remarks underscore fears that, 22 years after 9/11, Mr. Biden has grown complacent on the terror threat. Troubling signs are emerging here at home and in our own backyard of misdeeds by Iran and its proxies. Feature, say, Tehran’s murder-for-hire plot against the Iranian activist Masih Alinejad at her home in Brooklyn, the attack on Salman Rushdie, or the growing presence of Hezbollah in Venezuela, Monroe Doctrine notwithstanding. 

Clear-eyed, Mr. McCarthy sees how the president’s palavering with the mullahs has stoked danger. “Biden’s policy on appeasement,” Mr. McCarthy avers, “including money for hostage deals must come to an end.” The ex-speaker contends Mr. Biden’s “policy has only emboldened terrorists and handing over $6 billion to Iran only helps the cause.” He urges Mr. Biden to “make clear that harming any American will result in the wrath of the United States.” 

Which brings us back to the open Mexican border, at which, Mr. McCarthy warns, known terrorists are crossing over — more than 150 this year, he says, of whom we are aware. It raises fears, he says, that, if an attack on a par with Hamas’ against Israel happened here, it would lead to “30,000 Americans being murdered and slaughtered.” Unable to defend Mr. Biden’s record, his spokesman resorts to accusing his critics of wanting to “play politics.”

Perspective is in order. Israel is a country of 9 million ringed by foes. Its enemies present an existential threat. The potential harm from Iran and its agents to America would be, by comparison, less dire. Yet America learned on September 11 the destruction that even a handful of terrorists can wreak. Mr. McCarthy’s warning about Hamas’s attack on Israel, and Mr. Biden’s fecklessness, is an apt moment for America to take stock of rising national security risks.

Surely, for every captured border-crosser on the terrorist watch list, many are going undetected. Mr. McCarthy asks “What do they have planned and who are they communicating with?” He notes that “President Biden has said previously that he believes the number one threat to America is facing is climate change.” Not so, Mr. McCarthy contends. The principal threat to Americans, says the man who was second in line to the presidency, “is an open border.”