The Obama administration has hardly been soft against Iran. In addition to voting for U.N. Security Council sanctions against the country, in July 2010, Obama signed legislation that aimed to make it harder for the Iranian government to purchase refined petroleum and necessary materials to modernize Iran's oil and natural gas sector. The legislation also mandated that the U.S. government will no longer grant procurement contracts to businesses doing prohibited business with Iran.
And the president signed an executive order pushing further sanctions against Iran in November 2011.
There have been numerous reports of tensions and disagreements, and there have been times where Obama has expressed a view (as on settlement activity) not shared by his Israeli counterpart.
But any blanket assessment should also take into account assertions from the likes of Barak, lauding cooperation between the two nations over the last four years.