Why Vanguard would not deter Argentina in this Falklands counterfactual

Would retaining HMS Vanguard have deterred Argentina from invading the Falklands?

No, in this interpretation: Argentine leaders expected Britain to lack the will to fight and the United States to restrain a British response.

Vanguard's survival would not change the assumptions about political will identified in this counterfactual. Argentine leaders are understood to have expected Britain to decline a fight. They also expected their importance to the United States to prevent an effective British response. The further argument is that retreat would have carried wider Cold War consequences for Britain, giving it a reason to fight that Argentine leaders had missed.