Biden says Russian-linked cyberattack started "last year"

President-elect Biden said during his remarks in Wilmington on Tuesday that the Russia-tied cyberattack, which formerly was known to go back to as early as March, began "at least last year."

Why it matters: An administration source verified the earlier breach date — compounding the work and expense involved in rooting out the intruders, discovering what was lost and fixing for the future.

Details: The hack is known to have breached the Departments of Defense, State, Homeland Security, Treasury, Commerce and Energy and its National Nuclear Security Administration — plus the National Institutes of Health.

• Multiple global corporations were also infiltrated.

Our thought bubble: There’s a lot we still don’t know, but the growing list of key federal agencies struck alone is cause for serious concern. This may turn out to be the most consequential hack in U.S. history, and one that has spurred lawmakers of both parties to call for a firm response.

• Trump’s refusal to acknowledge what his own intelligence and national security experts are surely telling him will come as welcome news to the Kremlin.

Go deeper: Trump downplays Russian-linked cyberattack on U.S.