To look at a more recent event, Gallup ‘s Presidential Approval Ratings for August and September, 2001 were:

Do you approve or disapprove of the way President Bush is handling his job as President?

Approve
Disapprove
No Opinion
August 21-22, 2001
57%
34%
9%
September 21-22, 2001
90%
6%
4%

The phenomenon known as the ‘Rally around the President Effect’ as evidenced in this example of pre and post 9-11.

 

Example 1 – Vietnam War