Why do certain states ( USA, Brazil, etc) feel the need to found a brand new city to act as capital?

by standy85

I know that their reason was not to favour one city/state over another, but isn't it the same with the newly founded capital?

MrDowntown

The new capital cities keep one region from being favored over another: the USA's northern states vs. the southern ones, or Australia's New South Wales over Victoria.

Imagine that the Acts of Union was between two nations on equal footing. A capital for the new kingdom in either Edinburgh or London favors one of the merging states over the other.