The last time Vladimir Putin's regime felt threatened it did two things.
It cracked down hard on dissent at home and it started a war in Ukraine.
The last time the Kremlin felt it was on the ropes, Russians lost a measure of freedom and Ukraine lost some of its territory -- and thousands of its citizens lost their lives.
When mass street protests spooked Putin's regime and damaged its legitimacy back in 2011-12, it wasn't repression alone that restored its authority.
It was also the patriotic euphoria unleashed by Russia's annexation of Crimea, its hybrid war in the Donbas, and its confrontation with the West.
Call it Putin's Crimea drug.
It caused a euphoric hallucination.
It changed the conversation.
And for years it made dissent futile as well as dangerous.
But the euphoria from the Crimea drug has now clearly faded.
And the same issues, corruption, arbitrary rule, and fatigue with a regime that has been in power far too long are coming back to haunt the Kremlin.
In the wake of last weekend's unexpectedly large nationwide protests, it's already clear that a harsh crackdown is coming.
But what else is coming? What will be the new Crimea drug?
Because last weekend's protests have clearly spooked the Kremlin.
The Putin regime clearly feels threatened again.
And when this regime feels threatened, it becomes very dangerous for Russia's citizens -- and for Russia's neighbors.