Yes. There will be two interviews. The first one is to screen out the obviously ineligible (50 years old; Catholic; already went on a Birthright trip) and the second one is to screen out the dangerous people. The second one is also the make-sure-you’re-Jewish one.
It’s usually conducted at the airport while you’re standing there with your bags. A polite dude with a tie will ask you some questions. The first question will probably be something like, “What is your background in Judaism?” If you say you’ve been strict Orthodox all your life, the second question will be asked in Hebrew. If you answer the first question with “I was raised Jewish but haven’t really practiced since my Bat Mitzvah,” the second question might be something like “What was your Torah portion?”
For me, I said I went to Reform Sunday school all my life and the guy asked me if I knew any Hebrew. I said, “of course!”
He said: “Like what?”
Immediately, every Hebrew word I’d ever learned disappeared out of my head, which isn’t saying much. “Er… um… uh” I explained, as he regarded me steadily. I finally came up with “Shevet b’vakah shah! Hey!” [“Everybody be quiet! Hey!” - often screamed crowds of rowdy Jewlets].
The guy thought that was funny and asked me if I knew anyone on the trip. I said yes, my sister who is right over there. He rolled his eyes and sent me over to interview with her.
In a nutshell: they don’t care if you’re not terribly observant. Their goal, remember, is to increase pro-Israel sentiment in the world. Their target audience is people who might be susceptible to greater sympathy to a Jewish homeland: Jews, semi-Jews, sorta-Jews, kinda-Jews, and barely-Jews.
Oh and RickJay - Two words: Jewish Guilt. And also probably IDF Intelligence, who probably knew more about me when I went than I did.
I also want to reiterate what Anne Neville said. If you go, you’ll be surprised at how many people you’ll meet who share your political views, Israelis and Americans alike. As long as you believe that the state has a right to exist (an attitude evident in your willingness to work on a kibbutz), and you are polite, you should be accepted with open arms.