The way that Soviet intelligence tried to reshape the balance of power in the Middle East is essential to understand the developments that led to the outbreak of the Six-Day War.

In practical terms, Israel has become the eyes and ears of the United States in the Middle East. This arrangement has freed the United States from a heavy intelligence-gathering burden. But it has also forced the Americans to depend upon the Israelis.

If Israeli intelligence that has been shared with the United States - whether the National Security Agency, the C.I.A., the Defense Department, or the White House - is not safely guarded, Israel faces a major threat to its security. Cooperation with America's agencies is deeply embedded in Israel's intelligence community.

Israel has good reason to be concerned about its intelligence making its way to Moscow: Russia is a major player in the war in Syria on Israel's northern border, where it has also become a close ally of Iran and Hezbollah, Israel's sworn enemies.