International Law recognizes the countries bordering oceans and seas have, by the 1982 United Nations Convention on the Law of the Sea, ‘territorial waters extending 12 nautical miles. The Kerch Strait is (at it widest) a tad over nine (9) miles wide and runs between two land masses that are both Russian territory. As such, for any vessel to pass into the Sea of Azov, they must traverse through Russian territorial waters and within five (5) miles of Russian coastline. Russia thus controls the Sea of Azov ~ it is, for all intents and purposes, a Russian lake with Ukraine across the lake. The concept of ’freedom of navigation’ does not apply to a circumstance where a hostile country’s (or their pal’s) waships can ‘force’ their way through another country’s territorial waters into an inland sea or lake. To do so, risks war. Pure and simple.
Before folks decide to hose the sidewalks down with testosterone insisting the Russians should allow hostile (NATO) nation’s navies to pass through their waters, within five (5) miles of their coasts, to enter the Sea of Azov ask yourself if ‘freedom of navigation’ works both ways? If yes, I guess you would agree the Russian or Chinese or Iranian warships should be allowed to motor up the Saint Lawrence river into Lake Ontario with a ship, perhaps the Russian missile cruiser Moskva, armed with Kalibr (Tomahawk like) cruise missiles…? How many US cities/targets would be within the 200 mile range of those Mach 3 missiles? Would you be hearing a resounding “HELL NO” from the Americans living in New England? What goes around comes around, eh?