The Israeli prime minister's comments about the U.S. leadership looks a lot like meddling.
A few quick thoughts:
1) Netanyahu absolutely stepped in it by accusing the U.S. -- albeit indirectly -- of not feeling enough urgency about Iran. You just don't do that. Which is to say, you do it privately.
2) Hillary Clinton's comment that sparked Netanyahu's reaction -- she said that the U.S. has no red lines or deadlines re: the Iranian nuclear program -- seems almost designed to provoke.
3) I don't think Netanyahu was trying to meddle in the U.S. election by doing what he did, for two reasons -- 1) I'm under the impression he believes Romney is going to lose, and so he wouldn't bother wasting political capital on him; 2) I believe he's boiling over with frustration over the world's inability to stop Iran, and is deeply worried that it will soon be too late for him to do anything about it.
4) Nevertheless, what he did looks a lot like meddling, and the White House understands that in Florida, Ohio, and Pennsylvania, in particular, Romney could manage to move thousands of Jewish voters onto his side if it is perceived that Obama has grown hostile to Israel. The ferocious anti-Netanyahu reaction by the White House this week was meant to signal to Netanyahu: Don't you dare think of helping Romney in any way, by making any more statements that could be read as critical of Obama's handling of Iran. In other words, the White House politicized a Netanyahu statement that had its roots in something deeper than politics (if you like Netanyahu, you would say his statement is rooted in history; if you dislike him, you would be more apt to say the statement was rooted in neurosis and megalomania).