What can a president/prime-minister do to tackle anarchy? [closed]

Consider Bangladesh in the early 70s. The leaders at that time decided to form a one-party state (BAKSAL) with a promise to restore a multiparty system once the anarchy was eliminated.

The current government in Bangladesh says that their party was trying to solve anarchy at that time.

I believe they were moving toward autocracy or possibly a communist state (because USSR was directly involved in the birth of Bangladesh).

Can you propose some arguments against the formation of a one-party system at that time?

For example, I can think of martial law, national government, etc.