'imagine' przeciez nie wyraza ani 'demand' ani 'intention' lub 'proposal', a to jest ten wydzwiek semantyczny ktory musi towarzyszyc subjunctive ( bez wzgledu ze 'imagine' uzywa sie z podrzednym 'that-clause' co moze 'kusic')
>It was essential that this brave young officer were to be the first President of the USA.
tu natomiast nie zrobiles mandative subjunctive ( tego co chyba miales na mysli uzyc), ten subjunctive to jest podstawowa forma czasownka
It was essential that this brave young officer BE the first President- tu bedzie subjunctive
It was essential that this brave young officer BE NOT ( lub) NOT BE the first President- tu bedzie negative subjunctive
tu masz ten hypothetical were-subjunctive ( albo past subjunctive), ma inne znaczenie
Just suppose everyone were/was to give up doing this and that ...
albo
If this brave young officer were the president...