Am I concerned? friends ask me quietly, after we all publicly praise President Obama's monumental Cairo speech. The friends are usually, but not always, Jewish. They are all, like me, strong supporters of Israel.

The answer is that of course I'm concerned. I'm very concerned. But since when has a supporter of the state of Israel not been concerned?

These are, nonetheless, especially sensitive and worrisome times, not only because of Iran's bellicose threats, continued Palestinian attacks, and, yes, Prime Minister Benjamin Netanyahu's aggressive stance, but also because many of us aren't certain we know where this president will stand in a crisis.

I'm not pretending it's easy. I can't defend Netanyahu's decision to continue to expand existing settlements on disputed lands. To be honest, I can't even defend my own behavior when I happened upon two lines at the Transportation Security Administration checkpoint, as I did a few weeks ago at Dulles International Airport. I went out of my way to choose the line with four businessmen ahead of me, instead of getting behind a Muslim family trying to take apart their stroller.

As I cruise through security, I look back to see TSA officials taking dirty diapers out of the diaper bag. Are they wrong? No, of course not. Ninety-nine percent of Muslims are not terrorists, but in our experience, nearly 100 percent of the terrorists who have attacked us are Muslim.

That is why Obama's message of respect for Islam is so important. It is better, far better, for the Muslim world to hate us a little less, even if that is all the president accomplished. And there is reason to hope he accomplished far more.

It is critical to create an environment in which the moderate Muslims we hear too little from feel free to speak out, and let's hope the president's speech is a step in that direction. A speech like that is one none of us - Muslim, Christian, or Jew - has heard in a long time, and it is critically important that we do.

Moreover, Obama sensitively combined his speech in Cairo with a visit to the Nazi death camp at Buchenwald. It was a visit the president said he would remember for the rest of his life, and I have no doubt that is so.

The brutality of Nazi anti-Semitism ultimately forced most of the world to recognize the right to a Jewish state. In that way, it has been as powerful a force as the Israeli Air Force in Israel's security, which is why it is so important to Iran to deny its existence.

But it is not enough. The events surrounding the liberation of Buchenwald 64 years ago, powerful as they should always be, are not enough to provide a pillar for Israel for the next 64 years. A visit to Buchenwald is not enough to secure Israel's future. That is why, as always, I am worried.

Obama has stepped up to incredible challenges with a sense of confidence and a keenness of intelligence that no one, frankly, has a basis to expect of any president on his first day. I am proud that he is our president. But that doesn't mean he is incapable of making a mistake. It doesn't mean he should be freed from the influence of his friends.

Trust but verify, as another president so famously said - a motto that applies to both friends and enemies. For those of us who are strong supporters of the state of Israel, there has never been a more important time to make our voices heard.

Syndicated columnist Susan Estrich appears regularly in The Inquirer.