Looking at the context is helpful in understanding. Paul wrote a letter, not chapters (they came along in the second millennium), And the flow of this begins with chapter 12.
http://textsincontext.wordpress.com/2012/05/31/romans-13-in-context-sword-pacifism/
Zaac is correct, Poncho is correct and so are you Shodan.
The rulers, authorities, etc have to be obeyed according to the scripture.
The founding rulers and authorities drew up documents e.g. Declaration of Independence, Bill of Rights (First ten amendments) and the Constitution with the other Amendments. They were not monarchs but republicans (lower case "r").
These documents allow and encourage, freedom of speech (say what you will), freedom of the press (read what you will) freedom of association (hang with those you choose), redress of grievances (complain freely about whats bugging you), the Ballot Box (choose who will be in or out of office), all this within the scope of the consent of the governed (AKA to impeach or not to impeach) which is at least part of what Poncho is saying.
So when we do all these things above we are obeying the rulers and authorities and therefore the VERY scriptures zaac has mentioned.
When we speak out freely naming the evil which this administration and others have perpetrated (abortion, euthanasia, perversion, etc) we are in fact rebuking the unfruitful works of darkness as you have pointed out.
Personally, I try to be as respectful as possible towards the commander-in-chief when exercising my freedoms given to me by the rulers and authorities (actually by God) when speaking out and associating with like-minded folk concerning the oppressive evil being perpetrated by this administration as I have done concerning other administrations.
I do in fact pray for the current president, that he will do the right thing.
Starting with the FDR administration we have allowed our representative republic to become a socialist nation (IMO of course).
But that's the price of being (for a season) a representative government, we did it to ourselves (howbeit with no small part of stealth and deception on the part of those whom we consented to govern us)
I'm not giving up though and will use all these tools which our rulers have granted to defeat the greatest tyranny of all (slaughter of the unborn).
HankD