Re: ignoring the fact of Prior Art ?
You can of course have patents invalidated if you bring up prior art
Maybe. Mock patent trials have shown that juries often weigh first-to-file higher than first-to-invent ("newness") or obviousness. There's apparently widespread feeling among the US populace that ideas are "in the air", so to speak, and the bureaucratic procedure of filing a patent application is what really counts.
I believe one of my prior posts has a link to the relevant reference; if not, search for something like "East Texas" "patent" "mock trial".