Congress 'whacked' the budget by 1.5 billion dollars. = Congress 'whacked' 1.5 billion dollars from the budget.
Their priorities are (all) 'out of whack'. [=they do not understand what things are actually important]
I paid 'top whack' [=('US') 'top dollar'] for these items. [=I paid the highest amount possible]
(..) I haven't seen him. Just as well, probably. That whole thing in the jails-- I mean, when they start to whack the lawyers, that's when I draw the line. This goes to Kaylee Ehrmantraut, and that goes to Mr. and Mrs. Albert Sharp. (..)2013 TvShow: Breaking Bad Title: Blood Money Season: 5 Episode 9