A nuclear deal with Iran does not yet exist, and therefore Prime Minister Benjamin Netanyahu cannot know what is in it, US State Department Jen Psaki said on Thursday. "We've seen this movie before," Psaki said of skepticism from leadership in Israel over the nuclear talks.Earlier this week Netanyahu said that the current proposal to Iran would endanger Israel. "It would enable Iran to breakout to its first nuclear device within an unacceptably short time," Netanyahu told a gathering of American Jewish leaders in Jerusalem. Netanyahu also said he knows the contents of a framework proposal, offered to Iran by the US, Britain, France, Russia, China and Germany last month. But the Obama administration is skeptical."It sounds like he knows more than the negotiators," Psaki said, responding to claims that Netanyahu knows the details of the deal. Netanyahu's scheduled speech before Congress continues to be a contentious issue in both Washington and Jerusalem.Leading Democratic Senator Charles Schumer called on his fellow Democrats on Thursday to attend the address next month, saying the Israel-US relationship should “transcend” any political differences.“It’s always been a bipartisan policy,” Schumer said of the US-Israel relationship.“Democrats and Republicans have always worked together on it, we ought to keep it that way.”Some Democrats, including Vice President Joe Biden, have said they will not attend the speech.Schumer, a ranking member of his party, was instrumental in altering the strident tone of the US-Israel relationship in the summer of 2010, after Biden’s disastrous visit during which Israel announced the building of homes in the Ramat Shlomo neighborhood of Jerusalem. At that point, Israeli-US ties hit a nadir.After he went on the radio in New York criticizing US President Barack Obama for pushing Israel too hard, the president’s tone changed dramatically.On Tuesday, when asked whether he thought Republican Speaker of the House John Boehner “blindsided” Obama with his invitation to Netanyahu, the senator said on WAMC Northeast Public Radio that he thought it was a “bad idea” because “our policy toward Israel should always be bipartisan.”Michael Wilner and Herb Keinon contributed to this report.