For now, I can only find sources in Russian, e.g. this:
He makes an interesting argument:
For years now, Russia has been training the United States like Pavlov's dog, delicately preparing the Americans for their most important capitulation - the refusal to fulfill their allied obligations under Article 5 of the NATO Charter.
I agree there is a risk Putin thinks he has achieved this.
Traditionally, during the Cold War, the US would station US troops in pretty-much indefensible forward locations (eg West Berlin).
The theory was that these troops would be killed by any attack, and US allies could be confident that the loss of US lives would be enough to make sure the US responded.
Interestingly, NATO has prominently been pointing out the existence of "four multinational battalion-size battlegroups in Estonia, Latvia, Lithuania and Poland... led by the United Kingdom, Canada, Germany and the United States respectively"
https://www.nato.int/cps/en/natohq/topics_136388.htm
And repeating their commitment to article 5:
"Putin’s war affects us all and NATO Allies will always stand together to defend and protect each other," he said. The Secretary General also noted that NATO is deploying elements of the NATO Response Force for the first time in its history. "Today, French troops are arriving in Romania as the lead element of this force. Our commitment to Article 5, our collective defence clause, is iron-clad,"
https://www.nato.int/cps/en/natohq/news_192548.htm
The reluctance of Trump to back article 5[1] will cost lots of lives.
[1] https://www.brookings.edu/blog/order-from-chaos/2017/05/17/t...
The link posted was from 2015.
I'm unable to find any recent writing in English that indicates that he thinks that is a belief in Moscow.
Instead, on Twitter he shared this Feb 27 story (not by him) that indicated Putin has a great fear of NATO forces:
But this underestimates Russian respect for NATO’s conventional military power, which is far greater than its own. The only language Putin understands is force, and Moscow did not retaliate after Turkey shot down a Russian military plane in 2015 or when the United States struck and killed Russian mercenaries in 2018
https://www.foreignaffairs.com/articles/ukraine/2022-02-26/m...