The Obama administration refused to act aggressively against Russian hackers during the election because they believed that Hillary Clinton was going to win the White House, sources are telling NBC News.

“They thought she was going to win, so they were willing to kick the can down the road,” a U.S. official with knowledge of the scope of the hacking told NBC.

Some in the administration and in Obama’s intelligence community fingered Russia during the campaign for the cyber attacks, which the administration says led to the exposure of emails hacked from the Democratic National Committee and the email account of Clinton’s campaign chairman, John Podesta. But the administration has become more vocal about the intrusions since Clinton lost to Trump in last month’s election.

Trump supporters have asserted that the ramped up interest in the hacking is intended to cast doubt on the validity of the Republican’s White House win. Trump, who has not accused Russia of hacking, has also argued that the administration is only complaining now because Clinton lost.

“If Russia, or some other entity, was hacking, why did the White House wait so long to act? Why did they only complain after Hillary lost?” he tweeted on Thursday.

[dcquiz] Retired Adm. James Stavridis, who was floated as a possible Clinton running mate, has also said that the administration could have done more to confront Russia.

“In retrospect it certainly seems as though it was a mistake not to call the Russians sooner and respond to them in a very forceful way,” he told NBC.

Despite Trump’s claim that the administration only started complaining about hacking after he won the election, the administration did accuse Russia of attempting to influence the election during the campaign. Obama also warned Putin about hacking during September’s G-20 summit.

But Obama’s past comments about Russian aggression undercut his administration’s new confrontational tone. The prime example is Obama’s response to Mitt Romney’s claim in a presidential debate in 2012 that Russia is the U.S.’s “number one geopolitical foe.”

Obama mocked that assertion in another debate, saying that “The 1980s are now calling to ask for their foreign policy back because the Cold War’s been over for 20 years.”

The administration has not publicized evidence that Russia is behind the hacks. But officials with the FBI, CIA, and Office of the Director of National Intelligence have told reporters that there is strong evidence that Russian agents are behind the breaches.

On Wednesday, NBC News reported that spies working for American allies believe that Putin himself was involved in the hacking effort.

The question that is being debated within the intelligence community is whether the hacks were intended solely to help put Trump in the White House or to delegitimize the American electoral system.

On Thursday, Clinton told a group of campaign donors gathered in New York City that she believes that Russian president Vladimir Putin targeted her campaign for hacking because of a personal grudge he held against her from when she served as secretary of state. (RELATED: Putin Hacked Democratic Groups Because He Has A Personal Grudge Against Me)

In an interview with NPR that aired on Friday, Obama pledged to take action against Russia for the hacks.

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