The 'burden of proof' is on the plaintiff, since the defendant is presumed innocent until proven guilty. [=the plaintiff must prove that the defendant is guilty]
The 'tax burden' has been falling increasingly on the middle class. [=middle class people have been paying a greater portion of taxes]
For the rest of his life he 'was burdened' with the knowledge that he had done nothing to help them.
(..) SETH: Who do you hate, Danny? I hate anyone that isn't white Protestant. SETH: Why? They're a burden to the advancement of the white race. - Some of them are all right, I guess. - None of them are fucking all right, Danny. They're all fucking freeloaders. Remember what Cam said? (..)1998 American History X