Edward Said's phrase "speaking truth to power"  means naming names of actual present power, at the risk of loss of employment and attacks including punitive defamation lawsuits, false criminal charges, smear campaigns, exclusions from organizations, exile, imprisonment, reprisals against one's family and friends, and death.
It means vigorously and publicly fighting against such attacks. 
It means publicly exposing the crimes of present power in one's own community where one has the most influence, in an effort to immediately create more justice via potentially catalyzed public opinion mobbing against oppression.
It does not mean theoretical critical analysis of past events or generic historical analysis of underlying motives and social structures that have driven social changes elsewhere and in the past. It does not mean materially risk-free blah blah. 
It does not mean suicide. It means standing against one's own oppression as part of one's ontological liberation. It means life and truth.
Speaking truth to power is extremely rare in North America, in the heart of arguably the most accomplished indoctrination camp ever devised. Cowardice, servitude, and self-deception are the norm among intellectuals.
Regarding Israel and US(-Canadian) Zionism , James Petras puts it this way :
Most critics especially on the Left condemn all brutal acts of war and torture whenever they are committed, so this charge is a phony cover-up of Israel’s especially brutal conduct from the founding of the state. .Israel holds ‘world records’ in the number of towns and villages ethnically cleansed (over 500 and counting); number of refugees deported (4 million and counting); number of homes demolished (60 thousand and continuing); and has imprisoned more civilians per capita than any other country (250,000 and growing). Israel is the country with the highest number of protective US Security Council vetoes (over 100) preventing the world body from condemning Israeli war crimes.
Even as I write these lines, April 25, 2010, the news from Washington is that Congress has passed a new war-sanctions act, by a 95% majority imposing a virtual blockade of Iran, authored by AIPAC and backed by all the major Americans Jewish organizations. With the exception of a handful of writers and anti-Zionist Jewish activists, the vast majority of the progressive leftist, Marxist, anti-war and Palestinian organizations and intellectuals, even those critical of the Congressional vote, in fear and cowardice, refuse to name the intellectual authors and political promoters of this vile act of Congress.
The terrible power of the Zionist Power Configuration has run amok: the Jewish Congressional lobby, the liberals, progressives and neo-cons all together signed and promoted an act of Congress signed by over 330 Congress people rebuking Obama for publicly disagreeing with Netanyahu over the land grab in Arab Jerusalem. [...] the US Congress and White House are zionized occupied territory.
 "Representations of the intellectual" by Edward Said.
 As an example of sustained attacks: "This is what targeting a dissident tenured professor looks like in Canada" by Denis G. Rancourt.
 "Against Chomsky" by Denis G. Rancourt.
 "The Canadian Zionism Question" by Denis G. Rancourt.
 "War Crimes in Gaza and the Fifth Column in America" by James Petras.