jewish identity

In Deborah Tannen's book Finding My Father: His Century-Long Journey From World War I Warsaw and My Quest to Follow she writes that she asked her father, a man born into a hassidic family in Polish Warsaw before WWI, but who gave up religion after coming to the US as a teenager (Tannen writes that she recalls only one time being brought to a synagogue by her father and they did not stay long), whether he feels more American or more Polish.  Her father responded, "I feel like a Jew."  (p.97) 

From the latest Pew survey: "At the same time, 41% of young Jewish adults do not identify with any particular branch of American Judaism. Most of the people in this category are “Jews of no religion” – they describe their religion as atheist, agnostic or nothing in particular, though they all have a Jewish parent or were raised Jewish and still identify as Jewish culturally, ethnically or because of their family background."  

In other words, most young Jews do not feel Jewish at all.

Deborah Tannen knows she is Jewish and does not hide that fact.  Yet she struggles to define what being Jewish actually means to her.  "If I don't think Jewish is a race... what is it?  A religion?  Yes, but I'm not religious.  A culture?  I hear people talk about 'cultural Jews," but that term feels inadequate to me; "culture" does not go deep enough.  I'm more comfortable with the term "secular Jew"; that feels like a reasonable way to describe Jews who aren't "observant," but it still doesn't say what Judaism is.  Is it a nationality...?  Though this is a worthy goal, I feel that my nationality is American.  Is Judaism an ethnic heritage?  For me, that comes closest.  I'm Jewish because my parents and grandmothers -- I never knew my grandfathers -- and my parents' sisters and brothers, were formed by the Yiddish speaking orthodox Jewish communities of Europe they were all raised in, and they formed the community that raised me.  Especially my parents.  Especially my father."  (p. 98 Italics/emphasis mine)

If this is the definition of what makes one Jewish, it is no wonder that we are in the situation that we are in.  Neither the young people of today nor their parents were formed by "Yiddish speaking orthodox Jewish communities"; they were formed by secular, liberal American communities, where humanism, egalitarianism, and apple pie are what's important.  The Jewish culture of Eastern Europe is long gone and American Jewry, outside of Orthodoxy, has nothing to replace it with, no set of values or shared cultural experience that can be called uniquely Jewish in character.  How and why can/should one identify as a Jew when that identity has no meaning whatsoever?