No, let's. It is easily done, as history shows.
Nationalism - Wikipedia, the free encyclopedia
I disagree with your first point (i.e. 'let's'), but I do agree with your second (i.e. that they have often been confused).
The reason I disagree with the first one is that I believe that the promotion of a healthy patriotism is the best defence against nationalism, and here's why:
If a person knows the difference between the two, he's less likely to confuse them and fall into the clutches of nationalism. Also, if a society is patriotic, people won't feel a need for nationalism or other fanatical ideologies. It's like the basic rule that for every action there's an equal and opposite reaction. Lack of patriotism can also feed nationalism as a blind, irrational and fearful reaction to this lack of patriotism. And of course the same holds true in reverse: nationalism can make peopel embarrassed of showing their patriotism out of fear of being associated with nationalists.
To some degree that has happened to me. I find certain verses of the national anthem to be excessively nationalistic, and that turns me away from the anthem to some degree. However, apathy is equally harmful in that it leads people to not care for their fellowmen. I do belive though that schools do need to teach a healthy sense of patriotism, a love for our country, which could be tought in conjunction with a recognition that the earth is essentially one country, not necessarily in a political sense, but as a feeling of universal brotherhood.