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.
(..) About how you carry around all the horrible things you were forced to do Horrible things that won?t leave you. It seems that it would do you good to unload some of that burden. Things done during war are terrible. being ordered to kill ... killing to save yourself, killing to save others. (..)2008 Gran Torino