Biden's Mistake on Ukraine

Yesterday President Biden held a news conference. During the conference Biden answered a question about a possible US Response to a Russian invasion of Ukraine this way... (NBC):

Biden said Putin “will be held accountable” and has “never have seen sanctions like the ones I promised will be imposed” if Russia makes further moves against Ukraine. He added the U.S. would increase its troop levels in the region, including in Poland, keeping with obligations under the NATO treaty.

But Biden appeared to hedge his threats, distinguishing between a "minor incursion" and a full-blown attack.

"And it depends on what it does. It’s one thing if it’s a minor incursion and we end up having to fight about what to do and not do," Biden added.me

Why is that a bad answer? To me, and many others, it all but invites Russia to move in a "minor" sense against Ukraine. What does that look like? I don't know, but I know what the previous "minor" incursion looked like.

Now: Actually Biden's comment is understandable in light of the past incursions. Crimea has historically not been a part of Ukraine. It was a "gift" from an ex-Soviet Premier to Ukraine's administration. But there are not only over 90% Russian on the peninsula, but it also housed Russia's Black Sea Naval Station Sevastopol and access to the Mediterranean. 

But the green-light to "minor incursion" was assine.

The two or four provinces Russia now controls are also 75-90% Russian.

But historically Ukraine has been a part of Russia. In fact Kiev (or Kyiv) was the first Russian capital. It was in the Soviet Union or Russia for hundreds of years. How much should the Russias take or control of another country? With the world seeming to move towards division of countries based on nationality, this is a bad precedent. 

Countries that have divided along ethnic lines have included Czechoslovakia (now Czech Republic and Slovakia), Yugoslavia (6 new countries), Sudan (Sudan and south Sudan), Somalia (now 3 divisions) in addition to the 13 new nations out of Soviet Union. Does that mean the we give a free hand in all cases?