State A and State B ratified a treaty on co-operation in medical research (the Treaty). The representative of State B signed the Treaty because he received a big bribe from State A. Two years after the entry into force of the Treaty, the situation in State A changed in that State A is now required to carry out more onerous obligations under the Treaty then previously. State A is unhappy with the new situation and sends a note to State B informing State B that it will no longer fulfil its obligations arising from the Treaty because two years ago it bribed the representative of State B to sign the Treaty. State B has not reacted to the note.

Is the Treaty still in force between State A and State B? Briefly explain your answer.