I had second thoughts and finally reopened the landbridge from Cordoba to Morocco (but not Granada-Morocco), for a couple of reasons.
1) If Spain selects Morocco as a Crusade target, it has to fight right around the world to the holy land, then across North Africa, east to west, and doesn't have a hope of succeeding. Likely the Byzantines and other Muslim factions would deny it passage without a fight first. Crusade launch declares war and, provided the Almos have any ships and they are in the right places, the blockade situation will prevent the Spanish from getting it across the Straits of Gibraltar. It occurs to me that the landbridges were put here in the first place to give them a path to the holy land which didn't involve having to cross Europe, potentially being blocked by European factions hostile to them, for whatever reason.
2) Similarly, the Almos may find it impossible to ship troops from Africa to Spain, to prepare for the arrival of a crusade (or a conventional invasion attempt) because of the blockading situation.
Having reopened the bridges and restarted the campaign, the HRE launched a crusade to Morocco a few turns ago (1180s). They usually lack fleets at this stage but, even if they had them, blockading would still prevent their arrival by sea.
I closed the Flanders-Wessex bridge but it now occurs to me the same problem applies. I'm not sure whether the AI will realise that a crusade launched against Wessex, Mercia etc is doomed to fail. In the time it would take to establish fleets (for a faction lacking the 'trader' personality type) and gain naval superiority in the channel, most of the stuck crusaders will have deserted.
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