Q&A: Why France could not simply seize the Channel Islands

Why did France not seize Jersey or Guernsey as a nearby base?

Because the islands had substantial defenses and determined inhabitants, so taking them would have required a contested assault rather than an easy occupation.

The Channel Islands sat close to the French coast, but proximity alone did not make them undefended prizes. Jersey and Guernsey had substantial defensive structures. Taking either island would therefore require a genuine assault rather than a simple landing and occupation. The islanders’ independent character is presented as another cost an attacker would have to overcome.