If Franco's Spain attacked Gibraltar and Portugal

What would happen if Spain entered the Second World War, attacked Gibraltar, and invaded Portugal with German support?

He expects the Gibraltar attack to fail against a narrow, heavily defended front, Portugal to resist, and Spain itself to become a vulnerable Allied invasion route that Franco's regime might not survive.

Gibraltar was an exceptionally difficult land target because attackers would advance over a narrow front exposed to concentrated fire. A major assault might devastate the surrounding area without taking the fortress. Invading Portugal would create another determined opponent with defended borders and a strong commitment to independence. If Spain joined after American entry into the war, the Allies could choose the Iberian Peninsula rather than North Africa or Italy as a southern front. Spain remained deeply divided after its civil war, making Franco's regime unlikely to survive the consequences.