US Ambassador to Israel Dan Shapiro summed up Washington's view of Israel when he said there was no doubt in his mind the Jewish state was a "strategic asset" for the United States.

"I have to admit I took the title of the panel with a little curiosity that there should even be a question mark at the end of it," Shapiro said of the panel he was participating in at the 12th annual Herzliya Conference.

"Is Israel a strategic asset to the United States?" asked with rhetorical wonder.

"To me that is a statement of fact. Of course it is. And it isn't really a question that requires a lot of debate, although maybe it requires some explanation," Shapiro said.

"Obviously, what makes us allies is the common values and interests. We don't have a better ally in this very unstable and strategically critical part of the world.

"Clearly we share common goals in combating terrorist organizations, preventing the proliferation of weapons of mass destruction, and we have common enemies who are targeting both of us.

"What makes Israel a strategic asset for the United States is that it brings unique capabilities to the table to pursue those common interests.

"Our efforts to pursue them jointly are more effective than what we could do on our own," Shapiro explained.

Former US Ambassador Robert Blackwill also said Israel was a strategic asset to the United States, but noted many Americans weren't aware of it.

"I wanted to say that one of the reasons there is a question mark at the end of the panel title is that there is a sizeable group of Americans who critique the relationship and believe that Israel is a strategic liability," Blackwill said.

However, Blackwill, a Republican, said a report he did in tandem with former Clinton Administration Undersecretary of Defense Walter Slocombe proved the opposite.

"We looked analytically at the question of whether Israel is a strategic asset, we looked as analytically as we could," Blackwill said of the report.

"And we discovered in preparing this report over six months or so, that the analysis the ambassador just gave is not in most defenses of the Israeli-US relationship in the United States," he said.

"Instead, of course, the defense of the relationship is made on moral grounds, and democratic values grounds, and not on what the ambassador and I think should be the 'third leg' of that discussion of the US Israeli relationship from the American point of view – which is Israel's strategic contribution to America's vital national interests.

"When I started, I thought I would start with Google and get a list of all of the contributions Israel makes to American national security and interests. And last summer and fall when we were doing we discovered that no such list existed.

"So Walt and I developed the list - and it is exhaustive and impressive," he concluded.

Blackwill and Slocombe's report can be downloaded for free at the websites of the Washington Institute for Near East Relations.