@Indy
I think of nationalism as love of the state, or government. Patriotism is love of country, or culture. I don't think either equate to "my country right or wrong" until someone decides to take it to that extreme as some sort of moralistic philosophy. Nationalists get creepy exactly when it gets to the point where good is defined by what the country does, rather than the country being defined according to good.
Nationalism is most useful in something like a space race or a war, whereas patriotism is most useful for the ongoing collective effort of a national population. Nationalism can be the grease that gets things done, while patriotism can be what keeps them that way, or celebrates the good outcomes. Hardline Nationalism takes all the outcomes and calls them good, because the state has to be good, regardless of what it does.
Not being a polysci guy either (for whatever thats actually worth), that's how I tend to look at it.