Netanyahu's planned speech to Congress is already backfiring
When it was revealed that Israeli Prime Minister Benjamin Netanyahu had accepted Republicans' invitation to speak to a joint session of Congress this March, it provoked a political firestorm. Netanyahu's speech would almost certainly focus on Iran's nuclear program, an issue on which he and President Obama are fundamentally at odds. Many observers saw the speech as a grave breach of protocol by Netanyahu and, by Congressional Republicans, a naked attempt to undermine Obama's foreign policy.
Netanyahu's apparent goal was to bolster Republican opposition to Obama's Iran talks and to encourage along new US sanctions on Iran that would blow up the talks. But, now, it appears that Netanyahu's gambit is blowing up in his face. Congressional Democrats are furious with Netanyahu, and the speech may well have caused them to put off a critical vote on Iran sanctions, thus putting Netanyahu's goal further out of reach.
While some think the speech is also an attempt to boost Netanyahu's poll numbers at home in advance of March 17 elections, that's probably not his core motivation, and in case it's not clear that it will help his political standing. The speech probably hasn't buoyed Netanyahu yet in Israeli polls and opposition parties are seizing on it as a sign of Netanyahu hurting the alliance with America. Ultimately, the speech seems to be a sincere bid to head off a nuclear deal Netanyahu sees as catastrophic but that bid is backfiring.
Democrats are really, really pissed at Netanyahu
http://www.vox.com/2015/2/5/7978375/netanyahu-speech-congress