while President Obama has affirmed on various occasions that Israel will legitimately decide how defend its security, his officials, advisers and actions over five years tell a different story:

In April 2009, President Obama’s Vice-President Joseph Biden publicly warned Israel of the Administration’s opposition to any Israeli military action against Iran.
The same month, then-Secretary Clinton declared that American support in countering the Iranian nuclear threat was conditional on Israel making concessions to the Palestinians.
In September 2009, Obama adviser and supporter and former National Security Adviser under President Jimmy Carter, Zbigniew Brzezinski (whom Obama has praised publicly) said that, were Israel to launch a military strike at Iran, the U.S. should confront the Israeli planes and shoot them down.