This is an issue that has been much debated in the United States in recent years. To the American civic identity, defined by crucial founding and refounding documents like the Declaration of Independence, the Constitution, the Gettysburg Address and the “I have a dream” speech, this is foundational. I can't imagine an American nationalism that I would associate myself with that did not have that kind of civic foundation.
However, people who've looked profoundly at the United States have never believed that the civic definition of our unity would be sufficient. It was necessary, but not sufficient, so throughout our history, there has also been an appeal to other kinds of commonalities, including the joint efforts that we have made.
In Abraham Lincoln's first address, when he pleaded with the south not to leave the union, he invoked the mystic chords of memory, not principle. Lincoln, above all, knew what the principle of America was, but in appealing to the south, he wasn't talking about the principle of America; he was talking about the memory of shared struggle and shared sacrifice.
I would say that civic identity and national identity at their best can work together to produce a strong country.