This morning, Israeli Prime Minister Benjamin Netanyahu comes to the Oval Office to meet with President Obama.
The last time they met, in May 2011, Netanyahu offered the American president a lesson on Jewish history - in front of the cameras. President Obama had just given a speech on the need for Israel, in its peace talks with the Palestinians, to return to its pre-1967 borders with mutually agreed swaps. It was an uncomfortable moment.
Today's meeting comes in a different context, with Iran's nuclear weapons program the primary focus.
The U.S. and Israel agree on much on this subject, but the differences are important: red lines and timelines.
In terms of red lines, Obama says Iran must not be allowed to develop a nuclear weapon. Netanyahu says Iran must not even be permitted to garner the capability to develop a weapon - and he wants Iran to cease enriching uranium.
Israel also wants the U.S. to more starkly warn Iran not to proceed, more directly threatening the use of military force.
President Obama disagrees, saying "all options are on the table," and telling an interviewer "I don't bluff."
As for timelines, as President Obama made clear in his speech to AIPAC yesterday, he believes there's a cushion of time for diplomatic efforts and economic sanctions to work. And while the U.S. shares Israel's skepticism about Iran's agreement to return to the P-5 plus 1 diplomatic talks about its nuclear program - knowing that the country has used those talks as a stalling mechanism - the White House believes they should be allowed to work.
Israel feels more urgency about the timeline, given its proximity to Iran and threats that the leaders of that country have made about the Jewish state.
It should be noted that, though this is a delicate diplomatic dance, there may be some value in the U.S. and Israel, while speaking as a united team, not being entirely on the same page. If Israel is perceived as something of a wild card, that could theoretically scare Tehran while also giving the U.S. leverage in dealings with the Europeans.