How and why did President Johnson escalate US involvement in the Vietnam War?

lbjHow and why did President Johnson escalate US involvement in the Vietnam War? | Teacher mutimedia presentation
By 1963, Kennedy felt that the US military advisors had done all that they could. 
He decided to announce a phased withdrawal from Vietnam to be completed by 1965.
However, three events transformed the situation and meant that instead US involvement was instead rapidly stepped up.
Students should complete the activities in this worksheet using the multimedia presentation at ActiveHistory.co.uk