This video from the International Solidarity Movement calls for emergency protests at Israeli embassies, consulates and visa offices and asks concerned citizens of the US to contact the White House, the State Department and your Congressional reps imploring them to demand a thorough investigation of the attack by a credible third party.
Since June, 2009, the Free Gaza movement has been writing to governments and non-governmental agencies around the world expressing opposition to Israel’s continued blockade of the people of Gaza. Now, the group is calling for a massive letter-writing campaign. There are three templates you use to base your own missives on. One is a call to governments and non-governmental agencies. The second one is to UN officials (in this case, the UN High Commissioner for Human Rights), and the third one is tailored to send to specific government officials.

This is for the first time, people are uniting against Israel unanimously and in masses
Israel has probably taken a suicidal step