The Obama administration had definitive proof last August that Russia was meddling in the presidential election – but became so mired in secret debates over a response it only ended up expelling 35 diplomats and closing two compounds in the U.S., The Washington Post reported Friday.
One option included planting cyber "bombs" within the Kremlin's infrastructure, but the plan was being developed as President Barack Obama left office.
Any effort to advance that effort now rests with President Donald Trump, the Post reported.
"It is the hardest thing about my entire time in government to defend," a former top Obama official in on the Russia discussions said, lamenting the actions ultimately taken against the Kremlin. "I feel like we sort of choked."
Former White House chief of staff Denis McDonough, however, defended the response to Moscow's attack on the "heart of our system."
"We set out from a first-order principle that required us to defend the integrity of the vote," he told the Post. "Importantly, we did that.
"It's also important to establish what happened and what they attempted to do, so as to ensure that we take the steps necessary to stop it from happening again."
The Post's report was based on interviews with "more than three dozen current and former U.S. officials in senior positions in government" – and most of whom "agreed to speak only on the condition of anonymity, citing the sensitivity of the issue."
In August, CIA Director John Brennan first alerted the White House of Russian President Vladimir Putin's "direct involvement in a cyber campaign to disrupt and discredit the U.S. presidential race," according to the report.
It also included the hacking of the computers of the Democratic National Committee, as well as Moscow's "audacious objectives — defeat or at least damage" Democrat Hillary Clinton and "help elect her opponent, Donald Trump."
In addition, "hackers with ties to Russian intelligence services had been rummaging through Democratic Party computer networks, as well as some Republican systems, for more than a year," the Post reported.
In July, the FBI began its probe into Trump campaign ties to the Kremlin – and the hacked DNC emails were published by WikiLeaks on July 22.
The Obama White House discussed many options for a response over the following months.
They included "cyberattacks on Russian infrastructure, the release of CIA-gathered material that might embarrass Putin and sanctions that officials said could 'crater' the Russian economy," the Post reported.
In December, however, Obama approved the expelling of the diplomats, the closing of the two compounds – and "economic sanctions so narrowly targeted that even those who helped design them describe their impact as largely symbolic."
The Post described Obama's response as "modest."
The White House, the CIA, the FBI, the National Security Agency, and the Office of the Director of National Intelligence declined to comment for the report.