Bush's numbers rose dramatically after the attacks of 9/11 from between the 50s and 60s, to well into the 80s:
The two other times that Bush's numbers saw significant improvement were coincident with the initiation of the American and British ground assault in March, 2003, and with the capture of Saddam Hussein in December, 2003. Bush's numbers also saw a mild, arching surge prior to the 2004 election, but since Saddam Hussein's capture, his approval numbers have remained at or below 50%.
Since the beginning of 2005, in fact, his numbers have gone from hovering around 50% to hovering around 40%. The conventional wisdom is that this drop is due to the poor showing of his Social Security reform effort, the seemingly inexorable deterioration of the situation in Iraq, the very skeezy attitude of the Administration toward the acceptability of torture as employed by Americans or by our proxies overseas, the Federal Government's lack of preparedness for Hurricanes Katrina and Rita (and the metaphorical significance of that poor showing for their potential response to another major terrorist attack), the sour taste left in the mouths of many Americans by the NSA surveillance program, the Dubai ports deal, the Vice President shooting his friend during a hunting accident (in the face), the continuing scandal over the outing of a now proven undercover CIA operative for political purposes, massive congressional and administration corruption, spiraling national debt and the borrow-and-spend mentality of the Republican congress and administration (replacing the Democrats' earlier "tax-and-spend" addiction), and a growing sense that high gas prices, global change, and our dependence on foreign oil are all somehow related and all the President can do is declare our rather obvious addiction.
I can't help but recall Bill Safire's New Year's Op-Ed (12/30/2005) in the New York Times, entitled "The Office Pool, 2006". His Question 14:
Well, the assumption has always been that Bush's numbers will in fact rise. But the only major bumps in Bush's numbers were after 9/11, after the invasion of Iraq, after the capture of Saddam Hussein, and during the heavy campaigning of the 2004 election.
As Bush approval rises, historians will begin to equate his era with that of: (a) Truman; (b) Eisenhower; (c) L.B.J.; (d) Reagan; (e) Clinton.
My answer to Safire's question: (f) Nixon. Why? Barring the capture of Osama bin Laden (when's that gonna happen, anyway?), a major terrorist attack on US soil is the only event that historically would have any chance of raising his numbers, and yet it is entirely possible that such an attack would instead lead his numbers to plummet, after awakening in the American public the growing sense that this Administration has no idea how to manage our national security.
I hate to be cynical, but if the Administration guesses that terrorists pose a political as well as an economic and physical threat, can we now finally expect them to take national security seriously?