Washington appears irked at Netanyahu's intransigence, and his flouting of it on US soil. President Obama is in Indonesia which has the largest Muslim population in the world. Eyes are on the US to see how it will move the peace process forward, and Netanyahu's comments only serve to highlight failure in this regard.
Netanyahu is taking advantage of the opportunity to build support in the US. However, he needs to be careful. The US currently has a lame-duck Congress and a President who has not yet begin his reelection campaign in full swing. This means that the pressure is doubly relaxed on President Obama. Secretary Gates has already announced his retirement, and Secretary Clinton has been in Australia, far away from the State Department Briefing Room at Foggy Bottom. The aggregate effect is that Netanyahu is operating in an environment in which the cost of a US response is lower than usual.