in 1971 the conservatives formulated a long term plan to "take back " the country from increasingly becoming more left..
in 1987 the FCC abolished its Fiarplay doctrine demanding equal time for left-right viewpoints..
the right wing talk-radio circuit has been responsible for shifting the entire country towards the right almost subconsciously
so in essence talk radio has pushed politics for a long time now
The Powell Memo (also known as the Powell Manifesto)