Obama literally took the position that sending weapons was too provacative and might cause a violent Russian reaction. Oh wow. Look what happened.
Russia took Crimea, and once they got away with it, started trouble in Donbas, meanwhile, IIRC, Obama was busy with the Middle East (the Neverending war continues). I suppose Russia is like a python that swallowed a sizable animal: it needed some time to digest it, so no overt land grabs from Ukraine for a while, not even recognition for the puppet republics of Donetsk or Luhansk.
Meanwhile Trump came along, inviting Russia to dig dirt on Clinton, praising Putin as better than Obama, and getting friendly with other dictators such as the Kim gang in North Korea.
Then Biden got elected and Trump lead a putsch. It failed, but it rattled a lot of people. Then there was the fall of Kabul—at least South Vietnam held on for about 2 years after the US pulled out. This was a bit after covid-19, and was soon after an entertainer got elected president of Ukraine.
I guess Putin thought the could take advantage of the situation and invade.
Like Hitler and Trump, some people just don't know when to stop.
Again, Trump very clearly and concretely put the maximal pressure on countering Russia in at least 12 if not 20 years.
(Not that it really needs saying, but Trump's been President for only 6 years.)
Russia was a bit different 20 years ago.
Twenty years ago, people hated the US—and that was somewhat warranted—because Dubya invaded and occupied, or attempted to occupy, Iraq—win one for daddy, I suppose. I took a dislike to Putin after Kursk, but to many, he was still the cool one. This was 2 years before Abkhazia and South Ossetia.
There was even talk of Russia joining NATO around that time or before.
So there really wasn't a need, real or perceived, to get tougher with Russia.
Kind of like Hitler, though in this, Putin played/plays the role of Hitler (though admittedly less brutal with other Eastern Slavs), Ukraine is Czechoslovakia, and Crimea and Donbas are Sudetenland. Many let it happen for peace (kind of like when Ukraine gave up its nukes for peace back when Clinton and Yeltsin were presidents). Then Putin invaded the rest of Ukraine, and as after Hitler invaded Poland, the West gulped and figured they better take things more seriously.
As for being tough on Russia, Trump was/is no tougher on Russia than Chamberlain was on Germany in WWI.
