Ever read about "The War of The Worlds?" by Orson Wells?
I'm talking about the radio play and the effect it had on America as it was broadcast.
And you wonder why the US government would never admit to alien contact should it ever occur?
Of course alien contact would render most religions null and void. That would anger the majority of the world population. It would shake the south-eastern US like nothing it's seen before. Not to mention most of the other Christian nations.
True contact would probably be like the old b&w Twilight Zone episode: where aliens are selecting humans to visit their planet in huge numbers, only to be cooked. Of course the humans find this out too late.