Dissent these days seems to be a dirty word. The Bush administration has, at least since September 11th, usually termed any criticism of its policies "unpatriotic." -
TomPaine.com Quotes of interest in that regard:
"Dissent is the highest form of patriotism." -
Howard Zinn in the same article as above, not Thomas Jefferson, as often mis-attributed.
"It is the duty of every patriot to protect his country from its government." - Thomas Paine
"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." - Benjamin Franklin
"Guard with jealous attention the public liberty. Suspect everyone who approaches that jewel." - Patrick Henry
"We cannot defend freedom abroad by deserting it at home." Edward R. Murrow
"The spirit of resistance to government is so valuable on certain occasions that I wish it to be always kept alive." - Thomas Jefferson
"I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man." - Thomas Jefferson