What is really going on with Nigerian Branded of Democracy

To the best of my understanding, there are three arms of Government: The Executive, The Legislature and The Judiciary. The combination of the three of them is the Federal Government, therefore they are all responsible for the success or failure of any Administration.

But here in Nigeria, the Legislature is working for the failure and downfall of the Federal Government, as far as they are concerned their job is to pull down the Federal Government.