Sentence:  The moment of rupture between the “hippie” and “yuppie” manifestations of baby <WSD>boomerism</WSD> is typically dated to the first presidential term of Ronald Reagan—or, even more specifically, to the moment when Reagan (a bastion of the older “greatest generation”) was shot by John Hinckley (a baby boomer) (Casale and Lerman 2002, 128). 
Meaning of the word marked with <WSD> tags:  The behaviours and attitudes of baby boomers.