There is no doubt that the Jews in America have much to be thankful for. America today is a place of calm where it is possible for the Jewish community to live in peace and to continue their Jewish life unhindered.On the other hand, our Sages point out that tranquillity is not always positive. In America, along with the tremendous growth in Jewish life and institutions of Jewish education, there has been in many communities the most terrible "relaxation" of Judaism to the point that millions of Jews are so relaxed about their heritage that they are almost comatose.
So, how should a Jew in the United States approach the 4th of July? I think it would be very appropriate to take a little time for introspection, to think about how a Jew should use the freedom which was unavailable to so many of our ancestors. And, after having begun the day in the correct way (praying and studying Torah), it would quite acceptable to celebrate in the traditional fashion -- fly the flag, go on a picnic with family and friends...
And remember: Fireworks are dangerous; be careful!