Does a country in a, nominal or actual, civil war lose credibility when it's unable to control its territorial waters? e.g. Taiwan, Gibraltar possibly [closed]

Question

In every historical case since the establishment of the UN, when warships freely sail within the territorial waters of a country without prior approval, it was seen as a challenge to the authority and credibility of the receiving country to defend their territory. i.e. to defend their monopoly on violence which is the basis for every country.

With territorial waters being commonly recognized as the littoral areas within 12 nautical miles of the shoreline.

In the special case of civil wars, the effect is magnified because of the uncertain claims to legitimacy of any of the claimants.

Does the government of the receiving country of unauthorized intrusions lose credibility if they let the intrusion go unchallenged?

In other words, lose some of the strength of their claim to the monopoly of violence.

For example, recent events indicate that warships of the People's Liberation Army Navy (PLAN) of the People's Republic of China (PRC) have likely entered the territorial waters of the Republic of China (ROC), commonly known as Taiwan, unimpeded. (Or at least there are no reports indicating any attempts at preventing their entry)

Since presumably there was no invitation from Taipei, this suggests the PRC can freely send PLAN warships and have them navigate around without regard to the claims of Taiwan. Both sides are also, technically, still involved in an unsettled civil war.

This then suggests the authorities in Taipei are unable, or unwilling, to control their territorial waters. (Though they appear to have never claimed de jure independence, or even de facto independence directly, only indirectly.)

For an island country there's the extra factor that there are no other clear-cut internationally recognized boundaries after the territorial waters are violated. (With airspace being much more difficult to police and observe.)

Even landing troops on actual land would be a more ambiguous situation, due to the existence of marshes, wetlands, beaches, high tide/low tide, temporary islets, sandbars, etc..., which may be exploited to place troops in a more ambiguous situation that may have some leeway.

The combination of the above factors seem to indicate island countries of disputed sovereignty are especially sensitive to such losses of credibility.

(There may also be several intermediate scenarios that Taiwan could transition to, such as suzerainty, vassalage, tributary, etc...)

For an even clearer example, though without any claimed civil war, see Gibraltar (raised by Fizz in the comments below) for a comparable situation where unimpeded intrusions into unambiguous territorial waters by the Spanish Navy have already effectively challenged otherwise strong claims. Although the exact degree of loss of credibility is ambiguous.

Warships going back and forth means that Spain effectively exercises controls over water and airspace access, in addition to land access they already control.

The repeated shows of force by the Spanish Navy clearly implies that the ‘independence’ of Gibraltar exists at their pleasure.

(This is much more straightforward as there is clearly no way Gibraltar alone can be a viable polity if totally blockaded, whereas Taiwan island has the possibility of indefinitely sustaining a modest population.)

Answer 1

Answer before the question was edited:

Of course it can. A nation under attack does not cease to be sovereign, at the very least while there is still some unoccupied territory left. The status of a government-in-exile would get into murky precedents.

The status of Taiwan, however, is a bad case to generalize. Both ROC and PRC consider themselves to be successors of factions of the Chinese civil war, which has been frozen for almost a century. The PRC is not prepared to admit that there are two distinct, sovereign Chinas, and the ROC is extremely careful about how they put their official position even while they maintain a de facto sovereignty.

Follow-up after the answer was edited:

You are still assuming that might makes right and a lack of might causes rights to lapse. No. It just makes the other party the aggressor.