Testifying to Congress on Thursday, FBI Director Christopher Wray reminded us that the Islamic State threat has not gone away.

"As we speak," Wray said, "the [FBI] has about 1,000 active ISIS investigations in all 50 states."

The U.S. faces a continuing challenge in countering ISIS-inspired and directed terrorist plotting.

As we have sadly come to learn, ISIS' great success has been its ability to inspire fealty by an entrepreneurial mix of losers, psychopaths, and ideological true believers. But because of the profligacy of online propaganda and the careful steps ISIS takes to insulate its operatives and agents from detection, there is often a narrow window to detect and prevent a terrorist attack.

This is a major concern for British counter-terrorism services, but also one for the U.S.

Of course, the ISIS threat isn't just that of inspired recruits. It also consists of directed cells such as that which attacked Paris and Brussels in November 2015 and March 2016. While ISIS' infiltration-centric threat is most significant in Europe, a narrowly disrupted ISIS plot in July against an Australian passenger airliner proves the group can operationalize major terrorist plots anywhere.

Another longtime concern of U.S. and allied counter-terrorism services is the possibility of a visa waiver passport-holder entering the United States in order to carry out an attack. Fortunately, close intelligence sharing helps prevent many of these suspects from entering the United States.

But what more should the government do to confront the ISIS threat?

Well, put simply, it can keep doing what it's been doing.

President Trump should continue to empower U.S. intelligence agencies and the military to continue their escalation against ISIS around the world. This matters not simply in destroying ISIS command and control capabilities, but in degrading the sense of ordained purpose that has allowed ISIS to attract so many idiots to its banner.

Trump also deserves credit for his decision to retain a U.S. force presence in Iraq and Syria so as to prevent ISIS' territorial rebirth. At home, the government should improve its partnerships with vehicle rental companies so as to mitigate the threat of more New York-style terrorist attacks.

Nevertheless, the key is that we remain astute to the threat that ISIS poses. As we saw in London just last month, even false alarms illustrate the group's challenge to the pursuit of happiness. Even if one attack might not kill or maim that many people (although the families of the dead might suggest even a few casualties matter), each attack frays our society.

Counter-terrorism rightly remains the FBI's number one priority.