CNN  — 

When the US intelligence community first picked up signs in the fall that Russia could be preparing a new attack on Ukraine, President Joe Biden directed his administration to act – and fast.

Wary of repeating mistakes made in 2014, when the US and Europe were caught off guard by Russia’s annexation of Crimea, Biden directed his national security team to use every tool possible to try to deter Russian President Vladimir Putin while a possible invasion was still assessed to be several months away, a senior US official told CNN.

“What we have been doing is very calculated,” the official said. “But we only have about a four-week window from now” to pull it off, he added.

The response began with a flurry of intense diplomatic activity in early fall, including a trip by CIA Director Bill Burns to Moscow to warn Putin directly against making a move.

But as Russian troops continued to amass near Ukraine’s border, the quiet diplomacy quickly evolved into stark, public warnings to Putin to back down or face harsh sanctions and increased US military assistance to Ukraine. Top Biden officials are now emphasizing that the consequences would go above and beyond anything Russia faced after its land grab in 2014.

“The sanctions we imposed on Russia in 2014 were largely intended to inhibit the medium-to-long-term development of specific Russian state-owned firms by restricting their access to US capital markets and technology,” a White House official said.

In contrast, the options on the table now “would be overwhelming, immediate and inflict significant costs on the Russian economy and their financial system.”

The intelligence community came under fire in 2014 when Biden was vice president, over what some lawmakers said was a failure to predict Russia’s incursion into Crimea until it was too late. And after that attack, Biden’s push to arm Ukraine and impose extremely severe sanctions on Russia was largely overruled by President Barack Obama.

Now in charge, Biden has wanted to do things very differently, officials said.

“This administration has been much more proactive, and there is more of a realistic sense now that Putin is capable of absorbing a lot of pain in an effort to impose costs on the US and our allies,” said New Jersey Democratic Rep. Tom Malinowski, who served as the State Department’s senior most human rights official from April 2014 to January 2017.

That has resulted in far more robust intelligence-sharing with Ukraine about Russia’s planning than anything that occurred in 2014, sources familiar with the process said – partly because the Ukrainian government is “a more reliable partner” now than it was then, said one former senior NATO official, and partly because Biden firmly believes Ukraine cannot be left out of any discussions that concern its future.

The administration also shared unusually detailed intelligence early on about Russia’s movements with NATO, G7 and European allies early on, European diplomats told CNN.

“I did not see this same level of coordination in early 2014,” said the former senior NATO official, who retired in September 2021. “This administration has been much more multilateral in their approach – that is new, and it’s the result of leveraging a lot of positive work that has been done amid the Covid-19 pandemic to increase political cohesion and the exchange of information among partners.”

However, Malinowski and other officials noted the situation now is different from 2014 in important ways.

“What Putin is potentially preparing for here requires taking actions that are much more visible than what we saw in 2014,” Malinowski said. “The forces he is amassing are exactly the forces you would amass if you were preparing for an all-out land invasion of the country, which is not what happened in 2014 with Russia’s little green men.”

The Russian military is also “in a very different place in terms of capability, force structure, and posture compared to 2014-2015,” said Michael Kofman, the research program director in the Russia Studies Program at CNA. And the US has a much better understanding of that, said the former senior NATO official.

“We have increased intelligence capabilities, an increased eastern base posture, better satellite imagery, more political cohesion,” the former NATO official said. “That has all allowed the US and its allies to be much better forewarned than in 2014.”

Still, current and former officials told CNN they see some similar mistakes being made – and similar signs from Russia that it is not taking the US threats seriously.

“I am definitely seeing things that are being done better in terms of them taking the threat seriously and working very closely with our allies, which I think is essential,” said Lt. Gen. Ben Hodges, who served as commanding general of United States Army Europe from November 2014 to December 2017.

“But there are still a lot of mixed messages coming out of the White House and a couple of unforced errors that the Kremlin must be quite happy with,” Hodges said, including Biden’s disclosure earlier this month that sending US troops to Ukraine is not on the table.

“I agree this is not the time for US military action,” he said. “But why announce that? That was basically a concession while the Kremlin has only increased their demands.”

Biden’s comment also reinforced Russia’s belief that, especially after the withdrawal from Afghanistan, the US will not want to get bogged down in another war overseas.

The National Security Council is similarly wary of sending certain kinds of equipment and weapons to Ukraine that might be viewed by Russia as provocative, like air defense systems, at a moment when the US and its allies are trying to get Moscow to de-escalate. Obama refused to provide Ukraine with lethal aid at all, also wary of provoking Russia further – but that restraint did nothing to deter the continued attacks by Russian-backed separatists in eastern Ukraine or get Russia to relinquish Crimea.

“The biggest thing that provokes the Russians,” said Hodges, “is when we look weak and disjointed.”

An adviser to Ukrainian President Volodymyr Zelensky said that while the military assistance the US has already provided is “greatly appreciated,” it would not be enough to deter the kind of attack the Russians seem to be planning.

“The US military assistance, although greatly appreciated, is primarily aimed at deterring a 2014-15 green men and other Russian-orchestrated proxy attacks,” the adviser said. “Urgent air and missile defense technology is needed to confront an all-out Russian attack, and this has been requested over a month ago. There is confusion in Kyiv as to why this is being withheld in light of such overwhelming intelligence the Biden administration has shared.”

This story has been updated with comment from a Ukrainian presidential adviser.