The perversion of this thought is what has powered the West, especially the US for the past 75+ years. The conservative social and economic bend, especially neocons, practically worship the fact that "America is at its best when it has an enemy" and all we need to do to stimulate the economy is to give people something to fear. Well, that happened at 9/11 and our response to such things have been fear based for a decade plus. How is our economy now? As it turns out, you can't replicate the World War II circumstances as too much has changed - our manufacturing base is crap, our laws are dictated by moneyed private interests and lots, lots more. For all the fear and faux-patriotism, we've gotten a decimated middle class while the financial elites have plundered nations while telling us "If we don't, the terrorists win".
Fuck that notion. Plenty of Economists are the ones that have ruined this nation to enrich themselves like slimy soothsayers, whispering into the ear of the corporate elite who then direct the government to do their bidding. Yes, in a magical black and white world where EVIL ALIEN HITLERS are invading the entire world, cannot be reasoned with or engaged in any diplomacy maybe then that would help. However, they'd need to be SO powerful to get all of Goldman-Sachs and every investment bank and corporate empire to not even THINK about war profiteering - they'd need to fear for their lives so much profit is irrelevant and I'm not even convinced this is possible for the bankster cartels - and short of going up against an "Independence Day"-or higher level malicious invasion fleet, that isn't going to happen.
In a more realistic world any intelligent life that can make it to our planet in any way we can understand is more than likely benevolent or at least neutral. Those that call for war, even in "unification", will likely be misinformed and result in at best a misunderstanding that the rest of us need to smooth over with our new visitors and at worst peg us as a hostile and barbaric species that certainly should not be privy to advanced technology and may be labeled a threat to the galaxy in the near future as our scientific progress continues. We want someone more like Carl Sagan dictating our interactions with alien visitors, not Karl Rove and Donald Rumsfeld.