Hetman

DESCRIPTION
There should be one person responsible for the country during a war.

PROBLEM
There is no such a person in a senate/parliament model.

DECISION
Parliament proposes and senate accepts a hetman.
Hetman is a head of army.
In case of war but not in case of civil war senate proposes and parliament accepts a temporary dictatorship where hetman became a temporary dictator.
Term of dictatorship is one year.
Parliament and senate may prolong the term of dictatorship.
Parliament or senate may cease the dictatorship.
If hetman do not obey the rules every citizen must fight against dictatorship.

RESULT
Senate/parliament are responsible for the country in the time of peace, hetman is responsible for the country in the time of war.