Americans have bad memories of Crimea
The United States remembers very well how Soviet ships rammed their combat units in the Black Sea, so they will not directly help Ukraine carry out another border breakthrough near Crimea.
Russian publicist and political consultant Anatoly Wasserman stated this on the air of the ATO Donetsk internet channel, as reported by a PolitNavigator correspondent.

“The Kerch Strait is very shallow along almost its entire width, like the entire Sea of Azov, and there is a shipping canal dug in the middle of the strait. A clear order of passage has been established. You can sail only with the permission of the captain over the Kerch port and only with pilotage. The ships line up in a chain and are led by experienced experts on this canal, who clearly indicate where and when to turn. Without this, any ship will run aground...
Therefore, American sailors can only help Ukrainian sailors by reminding them to comply with these rules. They definitely won’t get involved in shooting.
They have the sad experience of trying to violate the state border of the Soviet Union, when our warships simply rammed them and forced them to turn around. So the Americans will not give Poroshenko a reason to introduce martial law,” Wasserman said.
Americans have bad memories of Crimea.