PM Saab I just shrunk your scope!
Is Project Management an exact science? I think Post Manhattan/Operations Research Project managers dealt with a narrow aperture as far as scope was concerned and software development was more or less constrained by hardware (which dint "allow" larger scope to begin with). So it was quite easy for PMs (BTW in US PMs get lower salaries than Senior Coders, quite justifiably) to get away with formalised ways of getting things done.
However this is no longer true of today's scenario when almost every Biz IT alignment can be made possible in no time (alas there is nothing like "no time"), translating into a poser for PMs to make it happen.
And the scenario gets darker with SOx deciding to add clauses like these
As Chinese said, "May you live in interesting times"