But a wide-ranging threat assessment issued Thursday by several federal and local agencies makes it clear that U.S. agencies are preparing for the possibility that Biden's inauguration could inspire additional threats to the U.S. homeland, including foreign influence operations and even drone attacks from extremists.
"Since the incident at the U.S. Capitol, Russian, Iranian, and Chinese influence actors have seized the opportunity to amplify narratives in furtherance of their policy interest amid the presidential transition," the threat assessment noted, citing at least once instance in which a Russian "proxy" promoted claims the rioters at the Capitol last week were actually members of the radical left-wing antifa movement who "disguised themselves" as Trump supporters.
Still, the assessment said the U.S. government has not identified any "specific, credible" information that suggests foreign nations might target critical infrastructure or U.S. personnel supporting the inauguration.
"Given the significant security failures of Jan. 6, D.C. and federal law enforcement will be ready this time for extremists and bad actors to return," said Brian Harrell, the recently-departed head of infrastructure protection at the Department of Homeland Security.
Every presidential inauguration, especially in the post-9/11 era, prompts increased security measures and an array of terrorism concerns from federal and local officials -- but next week's inauguration will be the first in which domestic terrorists are the focus of such nationwide concerns.
According to the threat assessment, domestic terrorists -- inspired by racist, anti-government or anarchist ideologies -- "pose the most likely threat to the 59th Presidential Inauguration."
"In light of the storming of the U.S. Capitol, planned events in Washington, D.C., in the lead-up to and day of Inauguration Day offer continued opportunities for violence targeting public officials, government buildings, and federal and local law enforcement," the federal warning concluded.
The 13-page threat assessment was one of many warnings, alerts and bulletins that the federal government has issued in recent days, with U.S. counterterrorism officials deeply worried that the next several days could bring even more violent -- and potentially fatal -- clashes.
Noting public "calls to violent action" that have been made ahead of the inauguration, the threat assessment warned that last week's clashes between rioters and law enforcement officers "will likely exacerbate [domestic terrorist] grievances, particularly militia extremists," and said that the time leading up to the inauguration on Wednesday "offers [domestic terrorists] more time to plan acts of violence."
The assessment included information gathered by the FBI, DHS, U.S. Capitol Police, Metropolitan Police Department, and three local intelligence fusion centers. It offered law enforcement partners in and around the nation's capital a look at the array of threats they could face on Wednesday, beyond threats from domestic terrorists.
The assessment made it clear that -- despite U.S. government successes in stemming the flow of Americans joining terrorist groups overseas -- U.S. officials remain concerned that Americans radicalized by ISIS or other foreign terrorist groups could seek to attack on Inauguration Day.
Such terrorists "remain a concern due to their ability to act with little to no warning, willingness to attack civilians and soft targets, and ability to inflict significant casualties with weapons that do not require specialized knowledge, access, or training," the assessment cautioned.
"We assess that the consumption of online violent extremist media remains one of several significant influences … in the radicalization and mobilization process of U.S.-based violent extremists, and such messaging may be interpreted by ISIS or al-Qa'ida supporters as encouragement to target mass gatherings or high-profile events" in Washington, the assessment added.
The assessment also warned that -- even if unlikely -- U.S.-based radicals could be inspired by violent drone attacks reportedly launched overseas.
"[W]e assess that unauthorized unmanned aircraft system (UAS) operations can disrupt law enforcement operations at the 59th Presidential Inauguration, present a hazard to civilians around the event, or delay the event's proceedings, though we possess no specific, credible information indicating malicious actors have plans to use UAS to target the 59th Presidential Inauguration," the assessment said.
Harrell, the former Homeland Security official, said he is particularly concerned about the violence that could come out of protests planned around the country this weekend.
With protests reportedly being planned at state capitols in all 50 states, "most states can quickly be overwhelmed by significant crowds, and they lack the resources to keep the Capitol grounds secure," he said.
Ultimately, Harrell said, "domestic terrorism, regardless of the political genesis, must be eradicated."
"Political extremists and perpetrators of targeted violence aim to weaken the very fabric of our democracy," he said. "Whether its origins are fringe conspiracies, anti-Semitism, ethnic supremacism, or something else, domestic terrorism of any form cannot and will not be tolerated in the homeland."