United States foreign policy can not have it both ways. The government can not wax poetic about "justice and freedom", while supporting autocratic and authoritarian regimes. Unfortunately, this is a standard that is hard to live up to. Many repressive countries have resources that we consume in high quantities, like oil from the Middle East.
It's not really the responsibility of the government to spread its ideals throughout the world. Add to that that I think Democracy is probably one of the worst systems ever, and you have why I don't think it should be promoted abroad by the United States in a nutshell. Space. Space.
The US Democracy is not perfect. They show great progress but they still don't take care of the people. They made them suffer by high taxes. Democracy means for the people, by the people which means the people rule and run the government through voting.
Here in the U.S. we like to promote individualism but when it comes to our foreign policies, aka nation building, it becomes completely hypocritical. Democracy isn't "one size fits all" and our Constitutional Republic, two parties version of it is just one amongst many. Not everyone wants to mimic our system because culturally speaking, they are not clones of us. They have different ways of thinking and national necessity may also dictate otherwise. As such, it is completely illogical and downright arrogant to expect them to adopt our version of Democracy without question.
I think the most effective method for the United States is to set an example. If the United States goes around forcing democracy on other nations and people, those nations and people will see democracy as a negative thing. The most effective means would be to set a passive example, where the people are free, happy, and successful. To bring to the world stage human advancement, like we did by going to the Moon. That is how you promote democracy and a free people with a free market.
In my opinion, I believe that there are many forms of national government that could be effective. It is in the interest of the United States government to promote any government abroad that encourages stability, prosperity, individual freedoms and human rights. There are dozens of Democratic states that have completely failed in just the last few years, while other types of government have remained effective.
My issue with Democracy is that, though it is the way things should be, it never can be, due to corruption and other such issues that plague all politics. The United States is not a Democracy. It is considered a Democratic Republic. It's a system that works, but it has issues with its own system, with corrupt politicians, and other things. Therefore, I think that the United States would not be a good country to be promoting Democracy. Though, there are worse examples out there, such as China.
With the current inflammatory situation in the Middle East, somehow, the United States feels that it must get involved in the business of other countries. We have no right to do this, because we are not mother or father to these countries. Other countries have already established their policies and how they deal with their people, and it is not our business to interfere, unless we merely supply humanitarian aid. However, supplying aid to people in other countries does not give the U.S. the right to go in and dictate what types of governments other countries should adopt.
The USA, as in its current situation, should not promote democracy, first of all because the other countries are their own countries, and so we have no right to do that. Sure we're powerful but that doesn't mean that the other countries have to listen to us. I believe that it is truly up to the countries own government to decide what type of governing system would it like to select.