The post-9/11 national security apparatus is still evolving

• "We learned a lot of important lessons," says Emily Harding, the vice president of the Center of Strategic and International Studies' Defense and Security Department.
• However, "we over-learned some lessons" — and "have drifted away from" others, she said.

Here are three broad ways the security pendulum has swung after 9/11:

Airport Security

9/11 reshaped airport security and led to the creation of TSA.

• It "changed the perspective: It went from efficiency first to security first," Jeff Price, an aviation security expert at Metropolitan State University of Denver, tells Axios.

But some security measures are inching back, like shoe removal mandates and restrictions on non-ticketed passengers passing through security.

• Republican Sens. Mike Lee (Utah) and Tommy Tuberville (Ala.) proposed the stalled "Abolish TSA Act" last year to eliminate the agency entirely, while the Trump administration announced — and later scrapped — a new private screening model.

People "want the security that post-TSA provides, but they want the efficiency that pre-TSA provided," Price says.

Surveillance and intelligence

Government surveillance powers rapidly expanded after 9/11, aimed at preventing the next threat.

• "In the days following 9/11, there was a willingness to do whatever needed to be done in order to protect us, and that's a natural psychological response," Harding says.
• But the public psyche has shifted toward privacy concerns.

Case in point: The USA PATRIOT Act was enacted in 2001, dramatically expanding government access to private records, but Congress later allowed some of the most controversial elements to lapse or amended them.

• Section 702 of the Foreign Intelligence Surveillance Act, another broad post-9/11 surveillance power that allows the government to collect data on non-U.S. persons living abroad, lapsed earlier this year for the first time since its creation.

Conversely, the Trump administration has supercharged some Bush-era strategies, labeling people "terrorists" and sending unauthorized immigrants to high-security prisons in the U.S. and abroad, Axios' Alex Thompson and Brittany Gibson previously reported.

• Atlantic Council fellow and veteran diplomat Daniel Fried writes in a Just Security essay that the administration has adopted a "loose and partisan definition of terrorism."
• He points to the U.S. Counterterrorism Strategy, which labels "Narcoterrorists and Transnational Gangs, Legacy Islamist Terrorists, [and] Violent Left-Wing Extremists" as major types of terrorist groups.

• "In the Trump administration, a threat (real or imagined) from a leftist group would be taken seriously and acted on, but a true threat from a far-right group might not be," he writes.

The other side: White House spokeswoman Lauren Bis said in a statement provided to Axios that "[t]he real threat to the Homeland was Biden releasing millions of illegal aliens unvetted into our country, including terrorists.

• She added: "Despite multiple Democrat shutdowns, we are fully equipped to keep Americans safe in an ever-changing threat landscape."

International security framework

The aftermath of 9/11 demonstrated the strength of alliances, with NATO's commitment to mutual defense invoked for the first time. But today, the U.S. is "burning through political capital for no good reason," Fried tells Axios.

• "The spontaneous outpouring of support and the credibility that the United States had after 9/11 that caused many countries to offer support in Afghanistan and ...even in Iraq, has been drained," he says. It's "not entirely" gone, he adds, but "that reservoir is much lower."
• He draws a sharp contrast between the support from allies in Iraq and that of the ongoing war in Iran.

Fried poses a question: "If the United States were hit again, would Canada come to our aid with troops now? Would Denmark?"

Go deeper: NYC unveils records suggesting officials knew air was unsafe after 9/11