Let's look at the first and foremost reason that the U.S. should not be engaged militarily in Libya. Who better to state the case than Congressman Ron Paul:
A no-fly zone is an Act of War. Now, what moral right do we have to participate in war activity against Libya? Libya hasn't done anything to the United States. They are not a threat to our national security. There's been no aggression. There's no Constitutional Authority for [Obama] to willy nilly go and start placing no-fly zones over countries around the world
Bottom line: Obama has lied to us once again and he does not have Constitutional Authority to engage militarily against Libya. Of course, the American public has been allowing the U.S. Government to ignore the Constitution for several decades now. But between Bush and Obama, the remaining shreds have been used as, in Bush's words, toilet paper.
But this war is also about the U.S. economy and oil. The former is an immediate gratification attempt to use war as a means to keep propping up our econmic system. The latter is to keep Libyan oil flowing to Europe, so that Europe does not "crowd out" the U.S. need to for oil from all of the other sources (the U.S. imports very little oil from Libya but most of Libya's exports flow to Europe, especially Italy).
And the bottom-bottom line for this country, Constitution-be-damned as Presidential toilet paper - is that we are already fighting fraudulent wars of terrorism in Iraq and Afghanistan that are financially bankrupting our future. I saw an estimate earlier that what is estimated to be a 3-month campaign will cost our taxpayers $9 billion. Because we are running a massive deficit already, the cost of this war will end up being financed with borrowed/printed money. An unConstitutional war with no real purpose or provocation being waged by a country which can't even afford to pay for its own domestic spending habits.
Obama is digging a deeper grave for this country while he and his wife hob-nob around Rio de Janeiro in 5-star hotels, spending even more taxpayer money on ridiculous amounts of luxury and personal security. The only Hope I have at this point is that someone like Ron Paul steps up in 2012 to get elected and really starts the long, painful road to reform and recovery.
Please keep in mind that the timeless historical formula for the collapse of a great empire is fractional banking, fiat currency and global imperialism. The U.S. is firmly on that path...