1980 vs other landslides

[bobloblaw]

What exactly about 1980 caused the dramatic coattail effect to flip the Senate to the GOP?  How come these coat tails weren't in effect for 1972 (I believe the GOP lost in the house) and 1984 (no real change) which were bigger presidential landslides?  Was it the money from the conservative interest groups or the candidates on the senate ticket?

1980 was 6 years after 1974, a big Dem year. So a lot of weak Dems won in 1974, vulnerable in 1980