That is a rhetorical question.
Yes, Obama can stop Putin.
IF Obama wants to do so, he can.
What Obama needs to do is rather simple. Ukraine needs lend lease military equipment; 10,000 soldiers trained; a removal of all tariffs; loans; help eliminating corruption; a massive PR campaign; and more jobs.
And few, if any, Ukrainians should be allowed to immigrate out of Ukraine.
I hate propaganda. But, Ukraine needs a massive PR campaign to stimulate the people to want to change. That is necessary to fight corruption.
I have already blogged on needed equipment and training. Train them about 200 miles from the Ukrainian border, to reduce the threat to Russia. Only allow them released for combat under reasonable conditions. Or, if you prefer, keep the controlled, so they do not start a war, just because they are wanting a war.
Loans are mostly on the way.
Removing the burden of excessive taxation upon the country. Russia, Europe, and the US tax Ukraine. That needs to stop, so Ukraine can afford to recover.
The economy in Ukraine is dependent upon ‘Russia.’ That means when Russia wants, Ukraine grows. When Russia wants Ukraine to stay weak, Ukraine stays weak.
The number one need in Ukraine are good jobs. And that means a strong border control is necessary, so young Ukrainians do not flee for Europe and the US.
Did I miss anything?