Reactions to former FBI director James Comey's testimony last week mostly seemed to follow predictable, partisan lines. To many Democrats, Comey appeared to be describing a clear case of obstruction of justice by President Donald Trump. To Republicans who support the White House, Comey's recounting of "leaking" his memos about conversations with Trump showed that he deserved to be fired.

But as a former FBI counterintelligence agent, what I saw as the most explosive aspect of the testimony didn't involve any legal violation of the U.S. code or questions about whether Comey had broken established Department of Justice protocols. Instead, it was the prima facie evidence that Comey presented that Trump appears unwilling to uphold his oath "to preserve, protect, and defend" the country – which puts the security of our nation and its democracy at stake. In the nine times Trump met with or called Comey, it was always to discuss how the investigation into Russia's election interference was affecting him personally, rather than the security of the country. He apparently cared little about understanding either the magnitude of the Russian intelligence threat, or how the FBI might be able to prevent another attack in future elections.

When Sen. Martin Heinrich, D-N.M., asked Comey whether Trump had ever appeared concerned about Russian interference or how to stop it in the future, Comey's answer was blunt: "No." After a moment of reflection, he added, without prompting, that he had "attended a fair number of meetings on that with President Obama." This contrast alone underscores Trump's disregard for his fundamental duty, which is to ensure the security of the nation, its government and its citizens from foreign enemies.

It's worth noting that there is unanimity among senior intelligence officials that the Russian interference in our election not only happened, but that it was extraordinary and unprecedented. In previous testimony, Comey described Russia as the "greatest threat of any country on earth," and he warned Thursday that Russia is "coming after America," regardless of party, "to undermine our credibility in the rest of the world."

Former CIA director John Brennan testified to Congress in May that he was shocked that Russia had "brazenly interfered" in the election, so much so that he took the extraordinary step of directly confronting his Russian counterpart. He added that he believes that even in the election's aftermath, "Russian intelligence services are trying to exploit what is going on in Washington now to their benefit and to our detriment."

It does not require an FBI investigation to see that a president of the United States who finds no reason for concern in any of these assertions – and indeed considers them a "hoax" – cannot have the best interest of the country at heart.

The FBI takes its counterintelligence mission extremely seriously, although it's usually less visible to the public than its law enforcement duties, which lead to arrests and criminal trials. Most of these activities, like the foreign agents they target, are by design covert, and they rarely see the inside of a courtroom. Many of the cases I worked as a counterintelligence agent involved foreign intelligence officers who used First Amendment and political freedoms in the United States to their advantage. This might involve disseminating propaganda by recruiting journalists (who did not realize they were spies) to write articles favorable to their government, or getting agents working on their behalf to lobby politicians for favorable policies toward their countries. (A rare glimpse into such a case that became public is the 2011 arrest of Syed Ghulam Nabi Fai, a lobbyist who pleaded guilty to conspiracy charges after the government accused him of being an agent for Pakistan's Inter Services Intelligence Directorate.)

The FBI can usually disrupt this threat under the radar – for instance, by delicately alerting unwitting individuals that they may be being targeted by a foreign power, or by identifying and recruiting an intelligence service's sources to become double agents for the United States. The Russia case is different, because its operation last year did not simply try to use the American system as a vehicle for Russia's benefit. Instead, Russia essentially attempted to break the system itself, by hacking political parties' computer and email systems, flooding the media with disinformation and purposely sowing political chaos in the voting process, which is the bedrock of our democracy. Although its activities didn't involve bombs or dead bodies, Russia's efforts were no less dangerous than any terrorist attack. In fact, the insidiousness of Russia's interference lies in its invisibility: The American public did not even know that their freedom of choice was potentially being manipulated and distorted for foreign interests.

For any president to ignore the situation is shocking. My former colleagues at the FBI who are working on this case and have uncovered the full scale of Russia's efforts must be incredulous at Trump's cavalier attitude.

To understand their perspective, consider this happening in the context we normally think of as a national security threat: Imagine that during the 2016 presidential election, a candidate publicly invited the Islamic State to bomb the Democratic Party headquarters. And then imagine that such a bombing in fact took place, resulting in the worst terrorist attack in U.S. history. Now further imagine that the new president not only had no interest in learning more about who caused the attack or bringing them to justice, but in fact went out of his way to make nice with the Islamic State and offer them political and diplomatic concessions. Finally, imagine that there may be evidence that members of the president's campaign or other American citizens were actively or passively involved in facilitating such an attack.

The fact pattern of the Russia investigation so far is similar – and that's an investigation Comey says Trump had no interest in following closely.

Regardless of which story line you believe about Comey's testimony, it is, in the end, a sideshow. The real issue is Russia's assault on our democracy and how we respond to it. If the president intends to stay true to his oath, both he and all Americans, regardless of political affiliation, will support the FBI in getting to the bottom of the Russian threat and making sure that it never happens again.