It is no secret that the US wants to support Ukraine up to the limit where the weapons supplied will be deemed to have enabled Ukraine to attack the Russian homeland. Despite that, there have been numerous cases where Ukraine has done just that (and incurred retaliation out of proportion with their incursions).
Currently, Ukraine is being attacked by missiles fired from ships in the Black Sea as well as drones from Russia-proper utilizing their 1,500km+ range.
If not making it legitimate for Ukraine to, for instance, target the facilities supplying electricity to Moscow, it should at least be kosher to supply weapons which can take out the ships firing missiles into Ukraine as they are at-sea rather than docked in Russian ports.
My guess as to why this has not taken place is two-fold:
Russia could pretty easily take out every military and merchant marine ship Ukraine has afloat in the Black Sea.
If, say the US, supplied the weapons the weapons used, Russia would feel obligated to retaliate. My guess this would be through Russian cyberattacks. These have been surprisingly missing during the conflict, other than “love taps” which show the ability to punch, but don’t deliver significant blows.
From a political standpoint in the US, while it is important to show the maximum “reasonable” support for Ukraine, it is also a reality that the US is trying to calibrate the support to avoid getting us involved in direct exchanges of blows with Russia. The same logic can be applied across the rest of NATO/EU/UK as well, not to mention why Israel does not supply “Iron Dome” anti-missile technology.
Russia is still far away from waging “total war” against Ukraine and she has been careful to avoid direct military conflict against a Western Europe which is satisfied to let Ukraine wear down Russian military capability without being directly involved. Western Europe is being asked to undergo significantly more financial and political hardship than the US in this effort and recent Italian electoral results indicate that the stress can possibly have long-term political consequences.
Jeff