Flat tax

A flat tax, also called a fixed rate tax, as well as other things similar to that, is a fixed tax rate which is applied to the population of a country / area as a whole, regardless of a resident's annual pay or living situation. For example, a mother working two jobs to keep her kid in school while living in a tiny council house which only has one toilet which is right next to the kitchen and therefore pretty gross would be paying the same amount in tax as a multi million-billionaire living in a massive country house with a racing car and a sexy wife where he has like 3 toilets and only one of them is in one of his 2 kitchens.

Due to the scathing example provided above, it's fairly obvious that a flat tax is an example of right wing financial philosophy.

The opposite of a fixed rate tax is progressive taxation, which is the liberal, and therefore right thing to do.