Lukeshenko never mobilized. He doesn’t dare put arms in the hands of the population at large.
If his small professional army were to be wiped out in an attack on Ukrainian forces, that would just make it all the easier for the Kremlin to move troops in and end the sovereignty of Belarus.
The problem for Russia is that they don’t have those troops anymore. Their most capable units have been mauled in the Ukraine war.
that would just make it all the easier for the Kremlin to move troops in
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The point is that Russia has no troops to move in.