Why did the republicans lose seats in the 1972 senate elections?

[brucejoel99]

I'd guess it's because 1966 was a wave Republican year, so 1972 was something of a reversal of that even though Nixon was personally reelected in a landslide.

I'd suspect this, as well, like how 2008 was such a good Democratic year w/ regards to the Senate that 2014 was always gonna be somewhat of a reversal of that, even if it had somehow managed to be a neutral (or even a narrowly Democratic) year.